Details of the Researcher

PHOTO

Masato Yoshida
Section
Graduate School of Engineering
Job title
Professor
Degree

  • 博士(工学) (Tohoku University)

Research History 4

  • 2025/06 - Present
    Tohoku University　Graduate School of Engineering, Department of Communications Engineering　Professor

  • 2011/07 - 2025/05
    東北大学電気通信研究所 准教授

  • 2007/04 - 2011/06
    東北大学電気通信研究所 助教

  • 2001/04 - 2007/03
    東北大学電気通信研究所 助手

Education 3

  • 東北大学大学院工学研究科電子工学専攻博士課程

    1997/04 - 2001/03

  • 東北大学工学部電気工学科

    1995/04 - 1997/04

  • 富山工業高等専門学校電気学科

    1990/04 - 1995/03

Committee Memberships 8

  • 電子情報通信学会　光エレクトロニクス研究専門委員会委員

    2021/06 - Present

  • 電子情報通信学会光ファイバ応用技術研究専門委員会　委員

    2017/04 - Present

  • 電子情報通信学会超高速光エレクトロニクス研究専門委員会　委員

    2017/03 - Present

  • ECOC　Program Member

    2019/04 - 2024/03

  • 電子情報通信学会　東北支部運営委員

    2020/06 - 2022/06

  • 電子情報通信学会　東北支部会計幹事

    2018/06 - 2020/06

  • レーザー学会　第40回年次大会実行委員会幹事

    2019/04 - 2020/03

  • 電子情報通信学会光通信システム研究専門委員会　委員

    2008/04 - 2014/03

Show all ︎Show first 5

Professional Memberships 5

  • IEEE photonics society

    2013/04 - Present

  • The laser society of Japan

  • Optical society of America

  • 応用物理学会

  • 電子情報通信学会

Research Interests 3

  • optical coherent transmission

  • mode-locked pulse laser

  • fiber laser

Research Areas 2

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Communication and network engineering / Ultrahigh-speed optical communication

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electronic devices and equipment / Applied Quantum Optics

Awards 13

  1. ICETC Best Paper Award

    2021/12　Performance comparison between injection-locked carrier frequency conversion and self-heterodyne detection methods in coherently-linked optical and wireless transmission for 6G

  2. テレコムシステム技術賞

    2021/03　10.16-Peta-B/s Dense SDM/WDM Transmission Over 6-Mode 19-Core Fiber Across the C+L Band

  3. ICETC Best Paper Award

    2020/12　BER performance improvement of ultrahigh-speed coherent Nyquist pulse transmission with low-nonlinearity, dispersion-compensated transmission line with chirped FBG and LCoS

  4. IEICE ELEX Best Paper Award

    2020/09　Wavelength-tunable sub-picosecond optical switch over entire C-band using nonlinear optical loop mirror

  5. 石田實賞（研究奨励賞特別賞）

    2019/11　デジタルコヒーレントQAM伝送に関する研究

  6. Best Paper Award

    2018/06　OECC2018　Reverse Phase Modulation Technique for GAWBS Noise Error Floor Elimination in 1024 QAM-160 km Digital Coherent Transmission

  7. 研究奨励賞

    2017/05　みやぎ産業科学振興基金　高速大容量デジタルコヒーレント伝送に関する多大な貢献

  8. International Wire & Cable Symposium, Inc, Jack Spergel Memorial Award

    2014/11/10　International Wire & Cable Symposium, Inc　Investigation of the Influence of Fusion Splice on Crosstalk Properties of Multicore Fiber

  9. 電子情報通信学会論文賞

    2012/05/26　電子情報通信学会　QAM Digital Coherent Optical Transmission Using Raman Amplifiers

  10. 第27回とやま賞

    2010/05/26　富山県ひとづくり財団　周波数安定化レーザの開発とそのコヒーレント光多値伝送への応用

  11. IEICE ELEX Best Paper Award

    2009/09/01　電子情報通信学会　Polarization and frequency division multiplexed 1 Gsymbol/s, 64 QAM coherent optical transmission with 8.6 bit/s/Hz spectral efficiency over 160 km

  12. 電子情報通信学会学術奨励賞

    2004/03　電子情報通信学会　フォトニック結晶ファイバと従来ファイバの接続における巨大フレネル反射の観測とその低減方法

  13. 青葉工学振興会研究奨励賞

    2001/12　東北大学青葉工学振興会　周波数シフト帰還型ファイバレーザを用いた光ファイバの分散パラメータ計測

Show all ︎Show 5

Papers 320

  1. 108 Gbit/s, 64 QAM fully-coherent mobile-fronthaul transmission over 10 km SMF and 70 m wirelessly in the 125 GHz band

    Tomoki Joichi, Arata Watanabe, Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    Optics Express　34　(4)　6345-6345　2026/02/12

    Publisher: Optica Publishing Group

    DOI： 10.1364/oe.579647 　

    eISSN： 1094-4087

    More details Close

    We report a 108 Gbit/s fully coherent optical-wireless transmission in the 125 GHz band for 6G mobile fronthaul. Using an injection-locked heterodyne detection scheme, we generated a 125 GHz-IF signal with a single-sideband phase noise of 3.2 degrees, which was sufficiently low for the demodulation of a 64 QAM data signal. By applying a digital pre-equalization scheme, we successfully transmitted an 18 Gbaud 64 QAM signal over a 10 km single-mode fiber and over 70 m wirelessly with a spectral efficiency of 5.71 bit/s/Hz.

  2. Novel Polarization-Dependence-Free Optical Injection-Locking Circuit Using $\lambda / 4$ Phase-Shift-Free HR DFB LD at $1.5 \mu ~\mathrm{m}$

    Keisuke Kasai, Shun Otsu, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2025 European Conference on Optical Communications (ECOC)　1-4　2025/09/28

    Publisher: IEEE

    DOI： 10.1109/ecoc66593.2025.11263060 　

  3. Guided acoustic-wave Brillouin scattering noise in few-mode fiber

    Masato Yoshida, Tetsuya Yoshida, Shohei Beppu, Yuta Wakayama, Noboru Yoshikane, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    Optics Express　33　(16)　34586-34586　2025/08/05

    Publisher: Optica Publishing Group

    DOI： 10.1364/oe.570713 　

    eISSN： 1094-4087

    More details Close

    We describe theoretical and experimental analyses of guided acoustic wave Brillouin scattering (GAWBS) noise in few-mode fiber (FMF). First, we theoretically show the mechanism of GAWBS noise generation through mode-coupling between different linearly polarized (LP) modes in FMF. We show that acoustic modes with wavenumbers along the fiber propagating axis contribute to the mode-coupling in the FMF. Next, we calculate the power spectra of GAWBS noise generated between identical LP modes, different LP modes, and degenerate LP modes in an FMF supporting six LP modes. We then measure the GAWBS noise spectra using a self-delayed heterodyne detection method and confirm good agreement with the calculated results. We find that GAWBS noise generated through mode-coupling between different LP modes exhibits reversibility with respect to the direction of the mode-coupling. Furthermore, we show that GAWBS phase noise generated between different LP modes is converted into intensity noise due to the different group velocities among LP modes in the FMF. We also clarify that the GAWBS noise coefficient is 3 to 4 dB higher than that in standard single-mode fiber (SSMF) since it experiences simultaneous mode-coupling from all LP modes. Finally, we evaluate the impact of GAWBS noise on digital coherent transmission with FMF using the Gaussian noise (GN) model and show that it can cause a substantial transmission distance penalty of as high as 27.7 ∼ 30.0%.

  4. Coherently-Linked Optical and Wireless Transmission for 6G Mobile Fronthaul

    Keisuke Kasai, Arata Watanabe, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2025 30th OptoElectronics and Communications Conference (OECC) and 2025 International Conference on Photonics in Switching and Computing (PSC)　1-3　2025/06/29

    Publisher: IEEE

    DOI： 10.23919/oecc/psc62146.2025.11110340 　

  5. Single-Channel 108 Gbit/s, 64 QAM Fully Coherent Mobile Fronthaul Transmission at 125 GHz-IF

    Tomoki Joichi, Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2025 30th OptoElectronics and Communications Conference (OECC) and 2025 International Conference on Photonics in Switching and Computing (PSC)　1-3　2025/06/29

    Publisher: IEEE

    DOI： 10.23919/oecc/psc62146.2025.11110001 　

  6. All-Digital 16 QAM Nyquist Pulse Transmission Over 4,000 Km

    Masato Yoshida, Takeki Serikawa, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2025 30th OptoElectronics and Communications Conference (OECC) and 2025 International Conference on Photonics in Switching and Computing (PSC)　1-3　2025/06/29

    Publisher: IEEE

    DOI： 10.23919/oecc/psc62146.2025.11109099 　

  7. Three-Dimensional Quantum Noise Stream Cipher with Time Domain Masking Peer-reviewed

    M. Yoshida, K. Kasai, T. Hirooka, M. Nakazawa

    European Conference on Optical Communication 2024　W2A.188　1-4　2024/09

  8. Fully Coherent Mobile Fronthaul Transmission with a Very Large Loss Budget by Using Injection-Locked Heterodyne Detection Peer-reviewed

    K. Kasai, K. Shirahata, M. Yoshida, T. Hirooka, M. Nakazawa, U. Azuma, T. Kobayashi

    European Conference on Optical Communication 2024　W2A.146　1-4　2024/09

  9. Coherent Nyquist optical pulse transmission at nearly 1-Tb/s/λ over 1,600 km with a capacity of 21.5 Tb/s using PS-32 QAM signals Peer-reviewed

    Shohei Beppu, Aoto Ishikawa, Takeki Serikawa, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    Optics Express　32　(9)　16533-16533　2024/04/19

    Publisher: Optica Publishing Group

    DOI： 10.1364/oe.518396 　

    eISSN： 1094-4087

    More details Close

    We demonstrate the 1,600-km transmission at nearly 1-Tb/s/λ signals with a capacity of 21.5 Tb/s. Probabilistic shaping was newly applied to high-speed coherent optical Nyquist pulse transmission systems to maximize the transmission capacity. Employing a 160-GBd PS-32 QAM format, WDM signals at nearly 1-Tb/s/λ were successfully transmitted over 1,600 km with a capacity of 21.5 Tb/s.

  10. Eigen-function division multiplexed coherent optical transmission in time domain by using higher-order Hermite-Gaussian pulses Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    Optics Express　32　(7)　12682-12682　2024/03/21

    Publisher: Optica Publishing Group

    DOI： 10.1364/oe.510189 　

    eISSN： 1094-4087

    More details Close

    We describe a new multiplexing technique and its application to demultiplexing in the time domain by using higher-order Hermite-Gaussian (HG) pulses, which are solutions of the Schrödinger equation. We call this technique eigen-function division multiplexing (EDM). This method enables us to further increase the total transmission capacity by superimposing many different HG pulses in the same time slot. This technique is different from a conventional optical time domain multiplexing (OTDM) technique using interleaving, where one pulse exists only in one time slot. The transmitted EDM HG pulses can be demultiplexed by adopting the time-domain orthogonality of the HG pulses (eigen-function orthogonality). The information carried by the mth-order HG pulse (HGm pulse) can be coherently detected by a photo detector, where photo-mixing with a phase-locked HGm pulse generated by a local oscillator can realize demultiplexing. The overlap integral with a different HG pulse becomes zero due to the time domain orthogonality. First, we show numerically that such a new EDM transmission scheme in the time domain is possible. We then show experimentally that we could successfully carry out an EDM HG coherent pulse transmission with four different HG pulses (HG0, HG1, HG2, and HG3), where we report a 400∼480 Gbit/s (10 Gbaud x 4 eigen-functions x 2 pol-mux.) 32∼64 QAM EDM transmission over 300∼450 km.

  11. New GAWBS Noise Interacting with Longitudinally Propagating Acoustic Waves in Few-mode Fibers Peer-reviewed

    M. Yoshida, T. Hirai, S. Beppu, K. Kasai, T. Hirooka, M. Nakazawa, Y. Wakayama, N. Yoshikane

    Optical Fiber Communications Conference 2024　W2B.22　2024/03

  12. Mode Division Multiplexed Coherent Optical Transmission in Time Domain by Using Higher-order Hermite-Gaussian Pulses Peer-reviewed

    M. Nakazawa, M. Yoshida, T. Hirooka

    Optical Fiber Communications Conference 2024　W2B.19　2024/03

  13. Experiments on the Generation of Higher-Order Hermite-Gaussian Pulses From an FM Mode-Locked Laser Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    IEEE Journal of Quantum Electronics　59　(6)　1-16　2023/12

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/jqe.2023.3305121 　

    ISSN： 0018-9197

    eISSN： 1558-1713

  14. Demodulation Performance Comparison of High-Speed Coherent Nyquist Pulse Signal with Analog and Digital Demultiplexing Schemes Peer-reviewed

    Masato YOSHIDA, Kosuke KIMURA, Toshihiko HIROOKA, Keisuke KASAI, Masataka NAKAZAWA

    IEICE Transactions on Communications　E106.B　(11)　1059-1064　2023/11/01

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1587/transcom.2022obp0001 　

    ISSN： 0916-8516

    eISSN： 1745-1345

  15. Efficient Optical-to-sub-THz Carrier Frequency Down-Conversion by UTC-PD-Integrated HEMT

    Tsung-Tse Lin, Mitsuki Watanabe, Dai Nagajima, Keisuke Kasai, Masato Yoshida, Tetsuya Suemitsu, Taiichi Otsuji, Akira Satou

    2023 International Topical Meeting on Microwave Photonics (MWP)　1-4　2023/10/15

    Publisher: IEEE

    DOI： 10.1109/mwp58203.2023.10416637 　

  16. Utilizing High-Intensity Optical Subcarrier Signal for Conversion Gain Enhancement of a UTC-PD-Integrated HEMT Photonic Double-Mixer Peer-reviewed

    T.-T. Lin, D. Nakajima, K. Nishimura, M. Watanabe, K. Kasai, M. Yoshida, T. Suemitsu, T. Otsuji, A. Satou

    2023 48th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)　2023/09/17

    Publisher: IEEE

    DOI： 10.1109/irmmw-thz57677.2023.10299383 　

  17. 16 Gbit/s, 256 QAM optical and wireless linked fully coherent transmission at 28 GHz using small microstrip antennas Peer-reviewed

    K. Shirahata, K. Kasai, M. Yoshida, T. Hirooka, M. Nakazawa, T. Kobayashi, U. Azuma

    European Conference on Optical Communication 2023　Tu.B.4.1　2023/09

  18. GAWBS Noise in Digital Coherent Transmission Invited Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    Journal of Lightwave Technology　41　(11)　3358-3371　2023/06/01

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/jlt.2023.3255942 　

    ISSN： 0733-8724

    eISSN： 1558-2213

  19. Measurement of 124-GHz E/O Modulation Bandwidth in Hybrid Modulation Laser Peer-reviewed

    Takumi Shima, Nobuhide Yokota, Masato Yoshida, Wataru Kobayashi, Hiroshi Yasaka

    IEEE Photonics Technology Letters　35　(10)　565-568　2023/05/15

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/lpt.2023.3263970 　

    ISSN： 1041-1135

    eISSN： 1941-0174

  20. Conversion Gain Enhancement of a UTC-PD-Integrated HEMT Photonic Double-Mixer by High-Intensity Optical Subcarrier Signal Peer-reviewed

    Dai Nakajima, Kazuki Nishimura, Mitsuki Watanabe, Tsung-Tse Lin, Keisuke Kasai, Masato Yoshida, Tetsuya Suemitsu, Taiichi Otsuji, Akira Satou

    Optical Fiber Communications Conference　2023/03

  21. Experiments on Generation of Various Dark and Bright Pulses From an FM Mode-Locked Laser Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    IEEE Journal of Quantum Electronics　58　(6)　1-23　2022/12

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/jqe.2022.3210339 　

    ISSN： 0018-9197

    eISSN： 1558-1713

  22. Distributed Measurement of Rayleigh Backscattered Crosstalk for Bidirectional Multicore Fiber Transmissions Using Multi-Channel Optical Time Domain Reflectometer Peer-reviewed

    Y. Kobayashi, T. Hayashi, T. Hasegawa, T. Suganuma, A. Inoue, T. Nagashima, H. Sakuma, T. Kikuchi, O. Shimakawa, H. Tazawa, M. Yoshida, M. Nakazawa

    European Conference on Optical Communication　2022/09

  23. Measurement of Mode-Coupling Along a Multi-Core Submarine Fiber Cable With a Multi-Channel OTDR Peer-reviewed

    M. Yoshida, T. Hirooka, M. Nakazawa, T. Hayashi, T. Hasegawa, K. Nakamura, T. Inoue

    European Conference on Optical Communication　2022/09

  24. Experimental and Numerical Analysis of Ultrahigh-Speed Coherent Nyquist Pulse Transmission with Low-Nonlinearity Dispersion Compensator Peer-reviewed

    Kosuke KIMURA, Masato YOSHIDA, Keisuke KASAI, Toshihiko HIROOKA, Masataka NAKAZAWA

    IEICE Transactions on Communications　E105.B　(9)　1014-1022　2022/09/01

    Publisher: Institute of Electronics, Information and Communications Engineers (IEICE)

    DOI： 10.1587/transcom.2021ebp3178 　

    ISSN： 0916-8516

    eISSN： 1745-1345

  25. UTC-PD-Integrated HEMT for Optical-to-MMW/THz Carrier Frequency Down-Conversion: Scaling Rule of Conversion Gain on UTC-PD Mesa Size Peer-reviewed

    D. Nakajima, K. Nishimura, T. Hosotani, K. Kasai, M. Yoshida, T. Suemitsu, T. Otsuji, A. Satou

    2022 47th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)　2022/08/28

    Publisher: IEEE

    DOI： 10.1109/irmmw-thz50927.2022.9895988 　

  26. Characterization of Inter-core Crosstalk of Multi-core Fiber as a Function of Bending Radius with Multi-channel OTDR Peer-reviewed

    Yuto Kobayashi, Takahiro Suganuma, Tetsuya Hayashi, Takemi Hasegawa, Masato Yoshida, Masataka Nakazawa

    2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC)　2022/07/03

    Publisher: IEEE

    DOI： 10.23919/oecc/psc53152.2022.9850127 　

  27. Demodulation Performance Comparison of 160 Gbaud Coherent Nyquist Pulse Signal with Analog and Digital DEMUX Schemes Peer-reviewed

    Masato Yoshida, Kosuke Kimura, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC)　2022/07/03

    Publisher: IEEE

    DOI： 10.23919/oecc/psc53152.2022.9849876 　

  28. 10.2 Tbit/s (1.28 Tbit/s/ch x 8 ch) WDM Nyquist Pulse Transmission over 2100 km Peer-reviewed

    Aoi Watanabe, Aoto Ishikawa, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC)　2022/07/03

    Publisher: IEEE

    DOI： 10.23919/oecc/psc53152.2022.9849931 　

  29. GAWBS noise in multicore fibers Invited Peer-reviewed

    Masato Yoshida, Masataka Nakazawa

    2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC)　2022/07/03

    Publisher: IEEE

    DOI： 10.23919/oecc/psc53152.2022.9849900 　

  30. Measurement of Wide-band Modulation Characteristic in Hybrid Modulation Laser Peer-reviewed

    Takumi Shima, Masato Yoshida, Nobuhide Yokota, Wataru Kobayashi, Hiroshi Yasaka

    2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC)　2022/07/03

    Publisher: IEEE

    DOI： 10.23919/oecc/psc53152.2022.9850031 　

  31. Software-Defined Fiber Optic Communications for Ultrahigh-Speed Optical Pulse Transmission Systems Peer-reviewed

    Mahdi Naghshvarianjahromi, Shiva Kumar, M. Jamal Deen, Taro Iwaya, Kosuke Kimura, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEEE Journal of Selected Topics in Quantum Electronics　28　(4)　1-10　2022/07

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/jstqe.2022.3190885 　

    ISSN： 1077-260X

    eISSN： 1558-4542

  32. 次世代RANの実現に向けたフルコヒーレントアクセスシステム Invited Peer-reviewed

    中沢 正隆, 葛西 恵介, 吉田 真人, 廣岡 俊彦

    電子情報通信学会論文誌 C　J105-C　(11)　315-328　2022/06

  33. Experiments on an AM Mode-Locked Laser as an Arbitrary Optical Function Generator Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    IEEE JOURNAL OF QUANTUM ELECTRONICS　58　(3)　2022/06

    DOI： 10.1109/JQE.2022.3165322 　

    ISSN： 0018-9197

    eISSN： 1558-1713

  34. Experiments on an FM Mode-Locked Laser as an Arbitrary Optical Function Generator Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    IEEE JOURNAL OF QUANTUM ELECTRONICS　58　(3)　2022/06

    DOI： 10.1109/JQE.2022.3165317 　

    ISSN： 0018-9197

    eISSN： 1558-1713

  35. Broadband injection-locked homodyne receiver for digital coherent transmission using a low Q Fabry-Perot LD Peer-reviewed

    Keisuke Kasai, Takashi Kan, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    Optics Express　30　(8)　13345-13345　2022/04/05

    DOI： 10.1364/oe.456327 　

    ISSN： 1094-4087

    eISSN： 1094-4087

  36. Precise Measurements and their Analysis of GAWBS-Induced Depolarization Noise in Multi-Core Fiber for Digital Coherent Transmission

    Masato Yoshida, Kozo Sato, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    IEICE TRANSACTIONS ON COMMUNICATIONS　E105B　(2)　151-158　2022/02

    DOI： 10.1587/transcom.2021CEP0006 　

    ISSN： 0916-8516

    eISSN： 1745-1345

  37. GAWBS noise correlation between cores in multi-core fibers

    Kozo Sato, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　29　(26)　42523-42537　2021/12

    DOI： 10.1364/OE.442261 　

    ISSN： 1094-4087

  38. Recent progress and challenges toward ultrahigh-speed transmission beyond 10 Tbit/s with optical Nyquist pulses

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    IEICE ELECTRONICS EXPRESS　18　(7)　2021/04

    DOI： 10.1587/elex.18.20212001 　

    ISSN： 1349-2543

  39. 10 Channel WDM 80 Gbit/s/ch, 256 QAM Bi-Directional Coherent Transmission for a High Capacity Next-Generation Mobile Fronthaul Peer-reviewed

    Masato Yoshida, Takashi Kan, Keisuke Kasai, Toshihiko Hirooka, Katsumi Iwatsuki, Masataka Nakazawa

    JOURNAL OF LIGHTWAVE TECHNOLOGY　39　(5)　1289-1295　2021/03

    DOI： 10.1109/JLT.2020.3034417 　

    ISSN： 0733-8724

    eISSN： 1558-2213

  40. Ultrahigh-Speed Nyquist Pulse Transmission Beyond 10 Tbit/s Invited Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS　27　(2)　2021/03

    DOI： 10.1109/JSTQE.2020.3011939 　

    ISSN： 1077-260X

    eISSN： 1558-4542

  41. Chromatic dispersion dependence of GAWBS phase noise compensation with pilot tone Peer-reviewed

    Kozo Sato, Takashi Kan, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　29　(7)　10676-10687　2021/03

    DOI： 10.1364/OE.418891 　

    ISSN： 1094-4087

  42. 10 Tbit/s QAM Quantum Noise Stream Cipher Coherent Transmission Over 160 Km Invited Peer-reviewed

    Masato Yoshida, Takashi Kan, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    JOURNAL OF LIGHTWAVE TECHNOLOGY　39　(4)　1056-1063　2021/02

    DOI： 10.1109/JLT.2020.3016693 　

    ISSN： 0733-8724

    eISSN： 1558-2213

  43. Experimental demonstration of distortion mitigation in 15 Tbit/s OTDM transmission using a cognitive dynamic system

    Mahdi Naghshvarianjahromi, Shiva Kumar, Jamal Deen, Taro Iwaya, Kosuke Kimura, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    26th Optoelectronics and Communications Conference　2021

    Publisher: OSA

    DOI： 10.1364/oecc.2021.t4b.8 　

  44. Single-Channel 1.28 Tbit/s Optical Nyquist Pulse Transmission over 3000 km with Roll-off Factor Optimization

    Aoi Watanabe, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    26th Optoelectronics and Communications Conference　2021

    Publisher: OSA

    DOI： 10.1364/oecc.2021.t4b.6 　

  45. Broadband Dynamic Injection-Locking Performance of Fabry-Perot LD and Its Application to Coherent Homodyne Receiver

    Takashi Kan, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2021 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC)　2021

  46. 64 Gbit/s, 256 QAM Transmission Through Coherent Optical-Wireless Link at 61 GHz Using Simple and High OSNR Carrier Frequency Converter

    Keisuke Kasai, Taisei Sato, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2021 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC)　2021

  47. GAWBS Noise Correlation Between Cores in Four-Core Fiber Peer-reviewed

    Kozo Sato, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2021 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC)　2021

  48. Spectrally efficient pilot tone-based compensation of inter-channel cross-phase modulation noise in a WDM coherent transmission using injection locking Peer-reviewed

    Takashi Kan, Kozo Sato, Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    OPTICS EXPRESS　29　(2)　1454-1469　2021/01

    DOI： 10.1364/OE.414381 　

    ISSN： 1094-4087

  49. Injection-locked 256 QAM WDM coherent transmissions in the C- and L-bands Peer-reviewed

    Takashi Kan, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　28　(23)　34665-34676　2020/11

    DOI： 10.1364/OE.404786 　

    ISSN： 1094-4087

  50. Precise measurements and their analysis of GAWBS-induced depolarization noise in various optical fibers for digital coherent transmission Peer-reviewed

    Masato Yoshida, Naoya Takefushi, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　28　(23)　34422-34433　2020/11

    DOI： 10.1364/OE.409326 　

    ISSN： 1094-4087

  51. Digital Coherent Optical Access Technologies for beyond 5G Network

    Keisuke Kasai, Masataka Nakazawa, Masato Yoshida, Katsumi Iwatsuki, Toshihiko Hirooka

    2020 IEEE International Symposium on Radio-Frequency Integration Technology, RFIT 2020　145-147　2020/09/01

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/RFIT49453.2020.9226206 　

  52. GAWBS phase noise characteristics in multi-core fibers for digital coherent transmission Peer-reviewed

    Naoya Takefushi, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　28　(15)　23012-23022　2020/07

    DOI： 10.1364/OE.399202 　

    ISSN： 1094-4087

  53. Evaluation of Systematic Errors in the Compact Absolute Gravimeter TAG-1 for Network Monitoring of Volcanic Activities

    Akito Araya, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa, Tsuneya Tsubokawa

    International Association of Geodesy Symposia　2020/04/29

    Publisher: Springer Berlin Heidelberg

    DOI： 10.1007/1345_2020_107 　

    ISSN： 0939-9585

    eISSN： 2197-9359

    More details Close

    Abstract Volcanic activities sometimes involve gravity changes, and this research is intended to establish an observation network surrounding an active volcano using compact absolute gravimeters. To simplify the configuration of absolute gravimeters, they are preferably operated with a light source distributed from a telecom band (wavelength of 1.5 μm) laser through optical fibers. To evaluate the accuracy of the absolute gravimeter with the telecom band laser, we conducted observations using a prototype gravimeter (TAG-1) with frequency-stabilized lasers at both 1.5 μm and 633 nm, and compared these results with the expected gravity at the site. Initially, both results showed offsets −187 μGal and −9.6 μGal for the 1.5-μm laser and the 633-nm laser, respectively (1 Gal = 10−8 m/s2). By correcting the systematic errors of the photo detectors measured by the synthetic chirp signal, the obtained absolute gravity was consistent with the expected value for both wavelengths; offsets from the expected gravity were reduced to 6.6 μGal and 5.4 μGal for 1.5 μm and 633 nm, respectively. We also evaluated the errors associated with long-distance transmission of the 1.5-μm laser using a reeled optical fiber (26 km) and an optical amplifier and found no degradation in the gravity data from the case of short transmission (10 m). These results allow networking of compact absolute gravimeters connected by telecom optical fibers that are operated using a common laser and expansion to volcanic areas to monitor the gravity change associated with volcanic activities.

  54. Theoretical and experimental analyses of GAWBS phase noise in various optical fibers for digital coherent transmission Peer-reviewed

    Naoya Takefushi, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　28　(3)　2873-2883　2020/02

    DOI： 10.1364/OE.384505 　

    ISSN： 1094-4087

  55. 64 Gbit/s, 256 QAM Coherently-Linked Optical and Wireless Transmission in 61 GHz Band Using Novel Injection-Locked Carrier Frequency Converter.

    Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    European Conference on Optical Communications(ECOC)　1-3　2020

    Publisher: IEEE

    DOI： 10.1109/ECOC48923.2020.9333340 　

  56. Low-Nonlinearity, Dispersion-Compensated Transmission Line with a Chirped Fiber Bragg Grating and Its Application to Ultrahigh-Speed Coherent Nyquist Pulse Transmission

    Taro Iwaya, Kosuke Kimura, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2020 OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC 2020)　2020

    ISSN： 2166-8884

    eISSN： 2166-8892

  57. Precise and Wideband Compensation of Inter-Channel Cross-Phase Modulation Noise in WDM Coherent Transmission Using Injection Locking

    Takashi Kan, Kozo Sato, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2020 OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC 2020)　2020

    ISSN： 2166-8884

    eISSN： 2166-8892

  58. Chromatic Dispersion Dependence of GAWBS Noise

    Kozo Sato, Takashi Kan, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2020 OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC 2020)　2020

    ISSN： 2166-8884

    eISSN： 2166-8892

  59. Wavelength-tunable sub-picosecond optical switch over entire C-band using nonlinear optical loop mirror Peer-reviewed

    Ryoya Hirata, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　16　(23)　2019/12

    DOI： 10.1587/elex.16.20190664 　

    ISSN： 1349-2543

  60. Suppression of large error floor in 1024 QAM digital coherent transmission by compensating for GAWBS phase noise Peer-reviewed

    Masato Yoshida, Naoya Takefushi, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　27　(25)　36691-36698　2019/12

    DOI： 10.1364/OE.27.036691 　

    ISSN： 1094-4087

  61. Numerical Investigation of Mutually Injection-Locked Semiconductor Lasers for Direct IQ-Signal Generation Peer-reviewed

    Nobuhide Yokota, Kazuya Komukai, Masato Yoshida, Hiroshi Yasaka

    IEEE PHOTONICS JOURNAL　11　(5)　2019/10

    DOI： 10.1109/JPHOT.2019.2934480 　

    ISSN： 1943-0655

    eISSN： 1943-0647

  62. Single-channel 15.3 Tbit/s, 64 QAM coherent Nyquist pulse transmission over 150 km with a spectral efficiency of 8.3 bit/s/Hz Peer-reviewed

    Masato Yoshida, Kosuke Kimura, Taro Iwaya, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　27　(20)　28952-28967　2019/09

    DOI： 10.1364/OE.27.028952 　

    ISSN： 1094-4087

  63. Experimental and theoretical analyses of GaWBS depolarization noise in digital coherent transmission

    Naoya Takefushi, Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    IET Conference Publications　2019　(765)　2019

    Publisher: Institution of Engineering and Technology

  64. Demonstration of on-line bi-directional 10-rrhs with an 80 Gbit/s/rrh capacity using 256 QAM WDM coherent transmission for next generation mobile fronthaul

    Takashi Kan, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Katsumi Iwatsuki, Masataka Nakazawa

    IET Conference Publications　2019　(765)　2019

    Publisher: Institution of Engineering and Technology

  65. Real-Time 256 QAM Bi-directional Coherent Transmission in Next Generation Mobile Fronthaul.

    Masato Yoshida, Takashi Kan, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC)(OECC/PSC)　1-3　2019

    Publisher: IEEE

    DOI： 10.23919/PS.2019.8817867 　

  66. Dual-Polarization On-Line 256 and 512 QAM Digital Coherent Transmission

    Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2019 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　2019

  67. Single-channel 10.2 Tbit/s (2.56 Tbaud) optical Nyquist pulse transmission over 300 km Peer-reviewed

    Toshihiko Hirooka, Ryoya Hirata, Jianping Wang, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　26　(21)　27221-27236　2018/10

    DOI： 10.1364/OE.26.027221 　

    ISSN： 1094-4087

  68. Single-Channel 7.68 Tbit/s, 64 QAM Coherent Nyquist Pulse Transmission over 150 km with a Spectral Efficiency of 9.7 bit/s/Hz Peer-reviewed

    K. Kimura, J. Nitta, M. Yoshida, K. Kasai, T. Hirooka, M. Nakazawa

    OECC 2018　5B3-4　2018/07

    ISSN： 2166-8884

    eISSN： 2166-8892

  69. 50.4 Tbit/s, 128 QAM L-band WDM Injection Locked Coherent Transmission over 160 km with Spectral Efficiency of 10.5 bit/s/Hz Peer-reviewed

    T. Kan, K. Kasai, M. Yosida, T. Hirooka, M. Nakazawa

    OECC 2018　5B3-3　2018/07

    ISSN： 2166-8884

    eISSN： 2166-8892

  70. 200 Gbit/s, 10 Gsymbol/s-1024 QAM Injection Locked Coherent Transmission over 160 km with a Pilot-Assisted Adaptive Equalizer Peer-reviewed

    K. Kasai, Y. Wang, S. Okamoto, M. Yoshida, M. Nakazawa

    OECC 2018　4B1-4　2018/07

    ISSN： 2166-8884

    eISSN： 2166-8892

  71. Reverse Phase Modulation Technique for GAWBS Noise Error Floor Elimination in 1024 QAM-160 km Digital Coherent Transmission Peer-reviewed

    M. Yoshida, N. Takefushi, M. Terayama, K. Kasai, T. Hirooka, M. Nakazawa

    OECC 2018　4B1-3　2018/07

    ISSN： 2166-8884

    eISSN： 2166-8892

  72. Single-channel 7.68 Tbit/s, 64 QAM coherent Nyquist pulse transmission over 150 km with a spectral efficiency of 9.7 bit/s/Hz Peer-reviewed

    Kosuke Kimura, Junpei Nitta, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    Optics Express　26　(13)　17418-17428　2018/06/25

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OE.26.017418 　

    ISSN： 1094-4087

  73. Single-channel 200 Gbit/s, 10 Gsymbol/s-1024 QAM injection-locked coherent transmission over 160 km with a pilot-assisted adaptive equalizer Peer-reviewed

    Yixin Wang, Seiji Okamoto, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    Optics Express　26　(13)　17015-17024　2018/06/25

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OE.26.017015 　

    ISSN： 1094-4087

  74. A New Optical Phase-Locked System between Ultrashort Pulses for 640 Gbaud Nyquist OTDM Coherent QAM Transmission Peer-reviewed

    Kosuke Kimura, Junpei Nitta, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    European Conference on Optical Communication, ECOC　2017-　1-3　2018/04/24

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/ECOC.2017.8345851 　

  75. Single-carrier 552 Gbit/s, 46 Gbaud 64 QAM Coherent Transmission over 100 km with Co-propagating 10 Gbit/s-OOK Signals Through a Deployed ROADM Network Peer-reviewed

    Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa, Masaki Shiraiwa, Yoshinari Awaji, Naoya Wada

    European Conference on Optical Communication, ECOC　2017-　1-3　2018/04/24

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/ECOC.2017.8345944 　

  76. Observation of guided acoustic-wave Brillouin scattering noise and its compensation in digital coherent optical fiber transmission Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Masaki Terayama, Seiji Okamoto, Keisuke Kasai, Toshihiko Hirooka

    Optics Express　26　(7)　9165-9181　2018/04/02

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OE.26.009165 　

    ISSN： 1094-4087

  77. 10.16-Peta-B/s Dense SDM/WDM Transmission Over 6-Mode 19-Core Fiber Across the C plus L Band Peer-reviewed

    Daiki Soma, Yuta Wakayama, Shohei Beppu, Seiya Sumita, Takehiro Tsuritani, Tetsuya Hayashi, Takuji Nagashima, Masato Suzuki, Masato Yoshida, Keisuke Kasai, Masataka Nakazawa, Hidenori Takahashi, Koji Igarashi, Itsuro Morita, Masatoshi Suzuki

    JOURNAL OF LIGHTWAVE TECHNOLOGY　36　(6)　1362-1368　2018/03

    DOI： 10.1109/JLT.2018.2799380 　

    ISSN： 0733-8724

    eISSN： 1558-2213

  78. Experimental and numerical comparison of probabilistically shaped 4096 QAM and a uniformly shaped 1024 QAM in all-Raman amplified 160 km transmission Peer-reviewed

    Seiji Okamoto, Masaki Terayama, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    Optics Express　26　(3)　3535-3543　2018/02/05

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OE.26.003535 　

    ISSN： 1094-4087

  79. 80 Gbit/s, 256 QAM Digital Coherent Optical Transmission with Injection-Locking for Next Generation Mobile Fronthaul Peer-reviewed

    Keisuke Kasai, Yixin Wang, Masato Yoshida, Toshihiko Hirooka, Katsumi Iwatsuki, Masataka Nakazawa

    European Conference on Optical Communication, ECOC　117　(423)　19-24　2018/01/29

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/ECOC.2017.8346036 　

    ISSN： 0913-5685

  80. Backward-Rayleigh-Scattering Suppressed 160 Gbit/s 256 QAM Injection-Locked Bidirectional Coherent Transmission for Next Generation Mobile Fronthaul.

    Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Katsumi Iwatsuki, Masataka Nakazawa

    European Conference on Optical Communication(ECOC)　1-3　2018

    Publisher: IEEE

    DOI： 10.1109/ECOC.2018.8535196 　

  81. Secure transmission using QAM quantum noise stream cipher with continuous variable QKD Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Takuya Hirano

    Optics InfoBase Conference Papers　2018　Th3E.2　2018

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OFC.2018.Th3E.2 　

  82. 4096 QAM (72 Gbit/s) single-carrier coherent optical transmission with a potential SE of 15.8 bit/s/Hz in All-Raman Amplified 160 km fiber link Peer-reviewed

    Masaki Terayama, Seiji Okamoto, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    Optics InfoBase Conference Papers　2018　Th1F.2　2018

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OFC.2018.Th1F.2 　

  83. Experimental and numerical comparison of probabilistically-shaped 4096 QAM and uniformly-shaped 1024 QAM in all-Raman amplified 160 km transmission Peer-reviewed

    Seiji Okamoto, Masaki Terayama, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    Optics InfoBase Conference Papers　2018　M3C.5　2018

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OFC.2018.M3C.5 　

  84. Injection-locked homodyne detection for higher-order QAM transmission Peer-reviewed

    Keisuke Kasai, Yixin Wang, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    Optics InfoBase Conference Papers　2018　M4G.1　2018

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OFC.2018.M4G.1 　

  85. Observation of guided acoustic-wave Brillouin scattering and its digital compensation in coherent QAM Transmission Peer-reviewed

    Masataka Nakazawa, Masaki Terayama, Seiji Okamoto, Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka

    Optics InfoBase Conference Papers　2018　M4B.2　2018

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OFC.2018.M4B.2 　

  86. Injection-locked homodyne detection for higher-order QAM transmission Invited Peer-reviewed

    Keisuke Kasai, Yixin Wang, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    Optics InfoBase Conference Papers　2018　M1.C.3　2018

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OFC.2018.M4G.1 　

  87. A 40 GHz, 770 fs regeneratively mode-locked erbium fiber laser operating at 1.6 mu m Peer-reviewed

    Koudai Harako, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　14　(19)　20170829　2017/10

    DOI： 10.1587/elex.14.20170829 　

    ISSN： 1349-2543

  88. 42.3 Tbit/s, 18 Gbaud 64 QAM WDM coherent transmission over 160 km in the C-band using an injection-locked homodyne receiver with a spectral efficiency of 9 bit/s/Hz Peer-reviewed

    Takashi Kan, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　25　(19)　22726-22737　2017/09

    DOI： 10.1364/OE.25.022726 　

    ISSN： 1094-4087

  89. Low-loss and reflection-free fused type fan-out device for 7-core fiber based on a bundled structure Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　25　(16)　18817-18826　2017/08

    DOI： 10.1364/OE.25.018817 　

    ISSN： 1094-4087

  90. 1024 QAM Coherent Optical Transmission In 31 Km-long, 19-core Fiber With Low Crosstalk And Large Effective Area Peer-reviewed

    M. Yoshida, K. Kasai, T. Hirooka, M. Nakazawa, K. Imamura, R. Sugizaki

    OptoElectronics and Communications Conference (OECC2017)　3-1K-2　2017/08

  91. QAM Quantum Noise Stream Cipher Transmission Over 100 km With Continuous Variable Quantum Key Distribution Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Takuya Hirano, Tsubasa Ichikawa, Ryo Namiki

    IEEE JOURNAL OF QUANTUM ELECTRONICS　53　(4)　8000316　2017/08

    DOI： 10.1109/JQE.2017.2708523 　

    ISSN： 0018-9197

    eISSN： 1558-1713

  92. 1024 QAM Coherent Optical Transmission In 31 Km-long, 19-core Fiber With Low Crosstalk And Large Effective Area Peer-reviewed

    M. Yoshida, K. Kasai, T. Hirooka, M. Nakazawa, K. Imamura, R. Sugizaki

    Opto-Electronics and Communications Conference (OECC 2017)　3-1K-2　2017/08

  93. Single-Channel 3.84 Tbit/s, 64 QAM Coherent Nyquist Pulse Transmission over 150 km with a Spectral Efficiency of 10.6 Bit/s/Hz Peer-reviewed

    J. Nitta, M. Yoshida, K. Kimura, K. Kasai, T. Hirooka, M. Nakazawa

    Opt. Express　25　(13)　15199-15207　2017/07

  94. Single-channel 3.84 Tbit/s, 64 QAM coherent Nyquist pulse transmission over 150 km with a spectral efficiency of 10.6 bit/s/Hz Peer-reviewed

    Junpei Nitta, Masato Yoshida, Kosuke Kimura, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　25　(13)　15199-15207　2017/06

    DOI： 10.1364/OE.25.015199 　

    ISSN： 1094-4087

  95. Single-Carrier 216 Gbit/s, 12 Gsymbol/s 512 QAM Coherent Transmission over 160 km with Injection-locked Homodyne Detection Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　Tu2E.1　2017

  96. Single-Channel 3.84 Tbit/s, 64 QAM Coherent Nyquist Pulse Transmission over 150km with Frequency-Stabilized and Mode-Locked Laser Peer-reviewed

    Masato Yoshida, Junpei Nitta, Kosuke Kimura, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　Th2A.52　2017

  97. 42.3-Tbits/s, 18-Gbaud 64QAM WDM Coherent Transmission of 160 km over Full C-based using an Injection Locking Technique with a Spectral Efficiency of 9 bit/s/Hz Peer-reviewed

    Takashi Kan, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　Th3F.5　2017

  98. 40 GHz, 770 fs harmonically and regeneratively FM mode-locked erbium fiber laser in L-band Peer-reviewed

    Koudai Harako, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    Optics InfoBase Conference Papers　2017　SM4L.2　2017

    Publisher: OSA - The Optical Society

    DOI： 10.1364/CLEO_SI.2017.SM4L.2 　

  99. Fabrication of Multi Core Fiber by Using Slurry Casting Method Peer-reviewed

    Jun Yamamoto, Tamotsu Yajima, Yusuke Kinoshita, Futoshi Ishii, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　116　(295)　29-33　2016/11/10

    ISSN： 0913-5685

  100. Fabrication of Multi Core Fiber by Using Slurry Casting Method Peer-reviewed

    Jun Yamamoto, Tamotsu Yajima, Yusuke Kinoshita, Futoshi Ishii, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　40　(38)　43-47　2016/11

    ISSN： 1342-6893

  101. 1.55 mu m hydrogen cyanide optical frequency-stabilized and 10 GHz repetition-rate-stabilized mode-locked fiber laser Peer-reviewed

    Masato Yoshida, Kazuki Yoshida, Keisuke Kasai, Masataka Nakazawa

    OPTICS EXPRESS　24　(21)　24287-24296　2016/10

    DOI： 10.1364/OE.24.024287 　

    ISSN： 1094-4087

  102. 440 fs, 9.2 GHz regeneratively mode-locked erbium fiber laser with a combination of higher-order solitons and a SESAM saturable absorber Peer-reviewed

    Toshihiko Hirooka, Kazunari Tokuhira, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　24　(21)　24255-24264　2016/10

    DOI： 10.1364/OE.24.024255 　

    ISSN： 1094-4087

  103. 1.55 mu m hydrogen cyanide optical frequency-stabilized and 10 GHz repetition-rate-stabilized mode-locked fiber laser Peer-reviewed

    Masato Yoshida, Kazuki Yoshida, Keisuke Kasai, Masataka Nakazawa

    OPTICS EXPRESS　24　(21)　24287-24296　2016/10

    DOI： 10.1364/OE.24.024287 　

    ISSN： 1094-4087

  104. 552 Gbit/s, 46 Gbaud, 64 QAM coherent transmission over 160 km with simple LD-based injection-locked homodyne detection Peer-reviewed

    K. Kasai, M. Yoshida, M. Nakazawa

    European Conference on Optical Communication (ECOC2016)　W.4.P1.SC5.51　2016/09

  105. Real-time 70 Gbit/s, 128 QAM quantum noise stream cipher transmission over 100 km with secret keys delivered by continuous variable quantum key distribution system Peer-reviewed

    M. Nakazawa, M. Yoshida, T. Hirooka, K. Kasai, T Hirano

    European Conference on Optical Communication (ECOC2016)　W.4.P1.SC5.59　2016/09

  106. 552 Gbit/s, 46 Gbaud, 64 QAM Coherent Transmission over 160 km with Simple LD-based Injection-locked Homodyne Detection Peer-reviewed

    K. Kasai, M. Yoshida, M. Nakazawa

    European Conference on Optical Communication (ECOC 2016)　W.4.P1.SC5.51　2016/09

  107. Real-time 70 Gbit/s, 128 QAM Quantum Noise Stream Cipher Transmission over 100 km with Secret Keys Delivered by Continuous Variable Quantum Key Distribution System Peer-reviewed

    M. Nakazawa, M. Yoshida, T. Hirooka, K. Kasai, T Hirano

    European Conference on Optical Communication (ECOC 2016)　W.4.P1.SC5.59　2016/09

  108. 320 Gbit/s, 20 Gsymbol/s 256 QAM coherent transmission over 160 km by using injection-locked local oscillator Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　24　(19)　22088-22096　2016/09

    DOI： 10.1364/OE.24.022088 　

    ISSN： 1094-4087

  109. A 295 mW output, frequency-stabilized erbium silica fiber laser Peer-reviewed

    Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2016 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　116　(195)　21-26　2016/08/25

    ISSN： 0913-5685

  110. A 1.55 mu m, 271 fs and 1.07 mu m, 294 fs simultaneously mode-locked Er- and Yb-doped fiber laser with a single SWNT/PVA saturable absorber Peer-reviewed

    Masatoshi Nakao, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　13　(14)　20160515　2016/07

    DOI： 10.1587/elex.13.20160515 　

    ISSN： 1349-2543

  111. B-13-31 Mode coupling measurement at a splice point of few-mode fibers using a synchronous multi-channel OTDR Peer-reviewed

    Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2016　(2)　452-452　2016/03/01

  112. 295 mW output, frequency-stabilized erbium silica fiber laser with a linewidth of 5 kHz and a RIN of -120 dB/Hz Peer-reviewed

    Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    Optics Express　24　(3)　2737-2748　2016/02/08

    Publisher: OSA - The Optical Society

    DOI： 10.1364/OE.24.002737 　

    ISSN： 1094-4087

  113. A 295 mW output, frequency-stabilized erbium silica fiber laser with a linewidth of 5 kHz and a RIN of -120 dB/Hz Peer-reviewed

    K. Kasai, M. Yoshida, M. Nakazawa

    Optics Express　24　(3)　2737-2748　2016/02

    DOI： 10.1364/OE.24.002737 　

  114. Fabrication of OH-free, single-mode fiber by using slurry casting and rod-in-tube method Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Yusuke Kinoshita, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　13　(1)　1-9　2016/01

    DOI： 10.1587/elex.12.20151005 　

    ISSN： 1349-2543

  115. Single-channel 40 Gbit/s digital coherent QAM quantum noise stream cipher transmission over 480 km Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    OPTICS EXPRESS　24　(1)　652-661　2016/01

    DOI： 10.1364/OE.24.000652 　

    ISSN： 1094-4087

  116. Optical and wireless-integrated next-generation access network based on coherent technologies Invited Peer-reviewed

    Toshihiko Hirooka, Masato Yoshida, Keisuke Kasai, Masataka Nakazawa

    Proceedings of SPIE - The International Society for Optical Engineering　9772　9772-2　2016

    Publisher: SPIE

    DOI： 10.1117/12.2211860 　

    ISSN： 1996-756X 0277-786X

  117. Fused Type Fan-out Device for Multi-core Fiber Based on Bundled Structure Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2016 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　Tu3I.2　2016

  118. A 295 mW Output, HCN Frequency-Stabilized CW Erbium Silica Fiber Laser with a Linewidth of 5 kHz and a RIN of-120 dB/Hz Peer-reviewed

    Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2016 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　W3E.1　2016

  119. Mode Coupling Measurement at a Splice Point between Few-Mode Fibers Using a Synchronous Multi-Channel OTDR Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2016 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　Th1J.4　2016

  120. A 0.95 ps, 10 GHz, 60 mW HCN Frequency-Stabilized and Mode-Locked Fiber Laser at 1.55 mu m Peer-reviewed

    Masato Yoshida, Kazuki Yoshida, Keisuke Kasai, Masataka Nakazawa

    2016 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　STu1P.3　2016

    ISSN： 2160-9020

  121. A 440 fs, 9.2 GHz Hybrid Mode-Locked Erbium Fiber Laser with a Combination of Higher-Order Solitons and a SESAM Saturable Absorber Peer-reviewed

    Toshihiko Hirooka, Kazunari Tokuhira, Masato Yoshida, Masataka Nakazawa

    2016 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　STu1P.4　2016

    ISSN： 2160-9020

  122. 1024 QAM, 7-core Fiber/Multi-core EDFA Transmission over 100 km with an Aggregated Spectral Efficiency of 109 bit/s/Hz Peer-reviewed

    Masato Yoshida, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    2016 21ST OPTOELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC) HELD JOINTLY WITH 2016 INTERNATIONAL CONFERENCE ON PHOTONICS IN SWITCHING (PS)　MB2-5　2016

  123. 320 Gbit/s, 256 QAM LD-based Coherent Transmission over 160 km with an Injection-locked Homodyne Detection Technique Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2016 21ST OPTOELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC) HELD JOINTLY WITH 2016 INTERNATIONAL CONFERENCE ON PHOTONICS IN SWITCHING (PS)　ThB3-3　2016

  124. Real-time adaptive 4-64 QAM, 20-60 Gbit/s quantum noise stream cipher transmission over 320 km with FPGA-based transmitter and receiver Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    European Conference on Optical Communication, ECOC　2015-　P.5.13　2015/11/30

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/ECOC.2015.7341787 　

  125. 448 Gbit/s, 32 Gbaud 128 QAM coherent transmission over 150 km with a potential spectral efficiency of 10.7 bit/s/Hz Peer-reviewed

    Keisuke Kasai, Yixin Wang, David Odeke Otuya, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　23　(22)　28423-28429　2015/11

    DOI： 10.1364/OE.23.028423 　

    ISSN： 1094-4087

  126. 80 Gbit/s, 256 QAM coherent transmission over 150 km with an injection-locked homodyne receiver Peer-reviewed

    Keisuke Kasai, Yixin Wang, Shohei Beppu, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　23　(22)　29174-29183　2015/11

    DOI： 10.1364/OE.23.029174 　

    ISSN： 1094-4087

  127. 1024 QAM, 7-core (60 Gbit/s x 7) fiber transmission over 55 km with an aggregate potential spectral efficiency of 109 bit/s/Hz Peer-reviewed

    Masato Yoshida, Shohei Beppu, Keisuke Kasai, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　23　(16)　20760-20766　2015/08

    DOI： 10.1364/OE.23.020760 　

    ISSN： 1094-4087

  128. HCN frequency-stabilized 10 GHz mode-locked fiber laser Peer-reviewed

    K. Yoshida, K. Kasai, M. Yoshida, M. Nakazawa

    ISUPT/EXAT 2015　P-34　2015/07

  129. HCN frequency-stabilized 10 GHz mode-locked fiber laser Peer-reviewed

    K. Yoshida, K. Kasai, M. Yoshida, M. Nakazawa

    International Symposium on Ultrafast Photonic Technologies/Extremely Advanced Transmission Technology (ISUPT/EXAT 2015)　P-34　2015/07

  130. Multi-core Fibers and Systems for Space-division Multiplexing Invited Peer-reviewed

    T. Hirooka, M. Yoshida, K. Kasai, M. Nakazawa

    Photonics North 2015　7.60　2015/06

  131. 2048 QAM (66 Gbit/s) single-carrier coherent optical transmission over 150 km with a potential SE of 15.3 bit/s/Hz Peer-reviewed

    Shohei Beppu, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　23　(4)　4960-4969　2015/02

    DOI： 10.1364/OE.23.004960 　

    ISSN： 1094-4087

  132. An 11.6 W output, 6 kHz linewidth, single-polarization EDFA-MOPA system with a (C2H2)-C-13 frequency stabilized fiber laser Peer-reviewed

    Akira Fujisaki, Shunichi Matsushita, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　23　(2)　1081-1087　2015/01

    DOI： 10.1364/OE.23.001081 　

    ISSN： 1094-4087

  133. Real-time 10 Gbit/s-16 QAM Quantum Stream Cipher Transmission over 320 km with FPGA-based Transmitter and Receiver Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    2015 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　W4F.4　2015

  134. Generation of 10 W, 100 fs, 10 GHz pulse train using high power EDFA-MOPA system with cascaded Raman pumping Peer-reviewed

    Akira Fujisaki, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2015 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　STh1L.7　2015

    ISSN： 2160-9020

  135. Real-time Adaptive 4-64 QAM, 20-60 Gbit/s Quantum Noise Stream Cipher Transmission over 320 km with FPGA-based Transmitter and Receiver Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    ECOC 2015 41ST EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION　P5.13　2015

    DOI： 10.1109/ECOC.2015.7341787 　

  136. QAM Quantum Noise Stream Cipher Using Digital Coherent Optical Transmission Invited Peer-reviewed

    M. Yoshida, T. Hirooka, K. Kasai, M. Nakazawa

    2015 49TH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS　1007-1011　2015

    DOI： 10.1109/ACSSC.2015.7421290 　

  137. 120 Gbit/s injection-locked homodyne coherent transmission of polarization-multiplexed 64 QAM signals over 150 km Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    Optics Express　22　(25)　31310-31316　2014/12/15

    Publisher: Optical Society of American (OSA)

    DOI： 10.1364/OE.22.031310 　

    ISSN： 1094-4087

  138. 120 Gbit/s injection-locked homodyne coherent transmission of polarization-multiplexed 64 QAM signals over 150 km Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　22　(25)　31310-31316　2014/12

    DOI： 10.1364/OE.22.031310 　

    ISSN： 1094-4087

  139. Measurement of mode coupling distribution along a few-mode fiber using a synchronous multi-channel OTDR Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    OPTICS EXPRESS　22　(25)　31299-31309　2014/12

    DOI： 10.1364/OE.22.031299 　

    ISSN： 1094-4087

  140. 140 Gbit/s, 128 QAM LD-based Coherent Transmission over 150 km with an Injection-locked Homodyne Detection Technique Peer-reviewed

    Y. Wang, S. Beppu, K. Kasai, M. Yoshida, M. Nakazawa

    ACP2014　ATh1E.3　2014/11

  141. A Single-channel 40 Gbit/s Digital Coherent QAM Quantum Stream Cipher Transmission over 480 km Peer-reviewed

    M. Nakazawa, M. Yoshida, T. Hirooka

    ACP2014　ATh4E.1　2014/11

  142. 140 Gbit/s, 128 QAM LD-based Coherent Transmission over 150 km with an Injection-locked Homodyne Detection Technique Peer-reviewed

    Y. Wang, S. Beppu, K. Kasai, M. Yoshida, M. Nakazawa

    Asia Communications and Photonics Conference (ACP2014)　ATh1E.3　2014/11

  143. A Single-channel 40 Gbit/s Digital Coherent QAM Quantum Stream Cipher Transmission over 480 km Peer-reviewed

    M. Nakazawa, M. Yoshida, T. Hirooka

    Asia Communications and Photonics Conference (ACP2014)　ATh4E.1　2014/11

  144. Single-channel 1.92 Tbit/s, Pol-Mux-64 QAM coherent Nyquist pulse transmission over 150 km with a spectral efficiency of 7.5 bit/s/Hz Peer-reviewed

    David Odeke Otuya, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　22　(20)　23776-23785　2014/10

    DOI： 10.1364/OE.22.023776 　

    ISSN： 1094-4087

  145. Real-time adaptive 4-64 QAM coherent optical transmission over 320 km with FPGA-based transmitter and receiver Peer-reviewed

    M. Yoshida, T. Hirooka, K. Kasai, M. Nakazawa

    ECOC2014　Th.2.5.2　2014/09

  146. 60 Gbit/s, 64 QAM LD-based injection-locked coherent heterodyne transmission over 160 km with a spectral efficiency of 9 bit/s/Hz Peer-reviewed

    Y. Wang, K. Kasai, M. Yoshida, M. Nakazawa

    IEICE Electron. Express　11　(17)　20140601　2014/09

    DOI： 10.1587/elex.11.20140641 　

  147. The Nyquist laser Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    OPTICA　1　(1)　15-22　2014/07

    DOI： 10.1364/OPTICA.1.000015 　

    ISSN： 2334-2536

  148. Adaptive 4 similar to 64 QAM real-time coherent optical transmission over 320 km with FPGA-based transmitter and receiver Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    OPTICS EXPRESS　22　(13)　16520-16527　2014/06

    DOI： 10.1364/OE.22.016520 　

    ISSN： 1094-4087

  149. B-10-47 1.92 Tbit/s, 64 QAM coherent optical Nyquist pulse transmission with a spectral efficiency of 7.5 bit/s/Hz Peer-reviewed

    Otuya David Odeke, Kasai Keisuke, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2014　(2)　415-415　2014/03/04

  150. B-13-9 Measurement of mode coupling distribution along a few mode fiber using multi-channel OTDR system Peer-reviewed

    Nakazawa Masataka, Yoshida Masato, Hirooka Toshihiko

    Proceedings of the IEICE General Conference　2014　(2)　505-505　2014/03/04

  151. QAM quantum stream cipher using digital coherent optical transmission Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai

    OPTICS EXPRESS　22　(4)　4098-4107　2014/02

    DOI： 10.1364/OE.22.004098 　

    ISSN： 1094-4087

  152. Investigation of the Influence of Fusion Splice on Crosstalk Properties of Multicore Fiber Peer-reviewed

    IMAMURA Katsunori, SUGIZAKI Ryuichi, YAGI Takeshi, YOSHIDA Masato, NAKAZAWA Masataka

    Technical report of IEICE. OFT　113　(406)　11-15　2014/01/24

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We investigated the relationship between splice loss and crosstalk properties in the fusion spliced multicore fibers. We observed the amount of crosstalk degradation under the different condition of splice loss and confirmed that the crosstalk degradation was related to the increase of the splice loss. We made the 43-km 7-core fiber transmission line with multiple fusion splice points considering the applicability for the real terrestrial transmission line. The relationship between fusion splice losses and crosstalk properties were measured by means of mode coupling measurement method utilizing an OTDR technique. As a result, the correlation between splice losses and crosstalk properties were clearly observed.

  153. A 380 fs, 40 GHz mode-locked erbium fiber laser with an MQW nonlinear PM/AM modulator using the pockels effect and the QCSE

    Masataka Nakazawa, Masato Yoshida, Ken Tsuzuki

    Optics InfoBase Conference Papers　2014

    Publisher: Optical Society of America (OSA)

    DOI： 10.1364/cleo_si.2014.stu1n.6 　

    ISSN： 2162-2701

  154. A 160 mW output, 5 kHz linewidth frequency-stabilized erbium silica fiber laser with a short cavity configuration

    Keisuke Kasai, Akira Fujisaki, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa, Shin Masuda

    Optics InfoBase Conference Papers　2014

    Publisher: Optical Society of America (OSA)

    DOI： 10.1364/cleo_si.2014.sw1n.4 　

    ISSN： 2162-2701

  155. Measurement of Mode Coupling Distribution Along a Few-Mode Fiber Using a Synchronous Multi-Channel OTDR Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    2014 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　22　(25)　31299-31309　2014

    DOI： 10.1364/OE.22.031299 　

  156. 1.92 Tbit/s, 64 QAM Coherent Nyquist Pulse Transmission over 150 km with a Spectral Efficiency of 7.5 bit/s/Hz Peer-reviewed

    David Odeke Otuya, Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2014 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　W1A.4　2014

  157. 2048 QAM (66 Gbit/s) Single-Carrier Coherent Optical Transmission over 150 km with a Potential SE of 15.3 bit/s/Hz Peer-reviewed

    Shohei Beppu, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2014 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)　W1A.6　2014

  158. A 380 fs, 40 GHz Mode-Locked Erbium Fiber Laser with an MQW Nonlinear PM/AM Modulator Using the Pockels Effect and the QCSE Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Ken Tsuzuki

    2014 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　STu1N.6　2014

    ISSN： 2160-9020

  159. A 160 mW Output, 5 kHz Linewidth Frequency-Stabilized Erbium Silica Fiber Laser with a Short Cavity Configuration Peer-reviewed

    Keisuke Kasai, Akira Fujisaki, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa, Shin Masuda

    2014 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　SW1N.4　2014

    ISSN： 2160-9020

  160. A 6 kHz Linewidth, Injection-Locked LD Using a Master Erbium Fiber Laser Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2014 OPTOELECTRONICS AND COMMUNICATIONS CONFERENCE AND AUSTRALIAN CONFERENCE ON OPTICAL FIBRE TECHNOLOGY (OECC/ACOFT 2014)　417-418　2014

  161. 60 Gbit/s, 64 QAM LD-based injection-locked coherent heterodyne transmission over 160 km with a spectral efficiency of 9 bit/s/Hz Peer-reviewed

    Yixin Wang, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　11　(18)　20140641　2014

    DOI： 10.1587/elex.11.20140641 　

    ISSN： 1349-2543

  162. OH-Free, Low Loss Single-Mode Fibre Fabricated by Slurry Casting / Rod-in-Tube Method Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Yusuke Kinoshita, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2014 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)　Th2.4.4　2014

  163. OH-Free, Low Loss Single-Mode Fibre Fabricated by Slurry Casting / Rod-in-Tube Method Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Yusuke Kinoshita, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2014 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)　Th2.4.4　2014

    DOI： 10.1109/ECOC.2014.6963829 　

  164. Real-Time Adaptive 4-64 QAM Coherent Optical Transmission over 320 km with FPGA-Based Transmitter and Receiver Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Keisuke Kasai, Masataka Nakazawa

    2014 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)　Th2.5.2　2014

    DOI： 10.1109/ECOC.2014.6963904 　

  165. 1.92 Tbit/s, 64 QAM coherent Nyquist pulse transmission over 150 km with a spectral efficiency of 7.5 bit/s/Hz Peer-reviewed

    David Odeke Otuya, Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    Conference on Optical Fiber Communication, Technical Digest Series　22　(20)　23776-23785　2014

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/OFC.2014.6886983 　

  166. OH-Free, Low Loss Single-Mode Fibre Fabricated by Slurry Casting / Rod-in-Tube Method Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Yusuke Kinoshita, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2014 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)　13　(1)　20151005　2014

    DOI： 10.1587/elex.12.20151005 　

  167. Detailed comparison between mode couplings along multi-core fibers and structural irregularities using a synchronous multi-channel OTDR system with a high dynamic range Peer-reviewed

    Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa, Katsunori Imamura, Ryuichi Sugizaki, Takeshi Yagi

    Optics Express　21　(24)　29157-29164　2013/12/02

    Publisher: Optical Society of American (OSA)

    DOI： 10.1364/OE.21.029157 　

    ISSN： 1094-4087

  168. Low-loss photonic crystal fiber fabricated by a slurry casting method Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　21　(25)　30500-30506　2013/12

    DOI： 10.1364/OE.21.030500 　

    ISSN： 1094-4087

  169. A single-channel 1.28 Tbit/s-58 km transmission in the 1.1 mu m band with wideband GVD and slope compensation Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　21　(23)　29055-29064　2013/11

    DOI： 10.1364/OE.21.029055 　

    ISSN： 1094-4087

  170. Nondestructive measurement of mode-coupling along a multi-core fiber using a synchronous multi-channel OTDR Invited

    M. Nakazawa, M. Yoshida, T. Hirooka

    International Symposium on Extremely Advanced Transmission Technology (EXAT 2013)　60-63　2013/11

  171. Generation of 9W, 4kHz linewidth 13C2H2 frequency-stabilized fiber laser output with erbium-doped fiber amplifier Peer-reviewed

    Fujisaki Akira, Kasai Keisuke, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2013　(2)　388-388　2013/09/03

    ISSN： 2160-9020

  172. Measurement of structural irregularity dependence on mode coupling along multi-core fiber using multi-channel OTDR system Peer-reviewed

    Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka, Imamura Katsunori, Sugizaki Ryuichi, Yagi Takeshi

    Proceedings of the Society Conference of IEICE　2013　(2)　382-382　2013/09/03

    DOI： 10.1109/PHOSST.2013.6614464 　

  173. 1 Tbit/s 256 QAM-OFDM transmission with 14.3 bit/s/Hz spectral efficiency Peer-reviewed

    Omiya Tatsunori, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2013　(2)　244-244　2013/09/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

  174. A single-channel 1.92Tbit/s, 64 QAM coherent optical pulse transmission over 150 Km Peer-reviewed

    Otuya David Odeke, Kasai Keisuke, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2013　(2)　242-242　2013/09/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

  175. A single-channel 1.92 Tbit/s, 64 QAM coherent optical pulse transmission over 150 km using frequency-domain equalization Peer-reviewed

    David Odeke Otuya, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　21　(19)　22808-22816　2013/09

    DOI： 10.1364/OE.21.022808 　

    ISSN： 1094-4087

  176. 1 Tbit/s 256 QAM-OFDM transmission over 560 km with 14.3 bit/s/Hz spectral efficiency Peer-reviewed

    T. Omiya, M. Yoshida, M. Nakazawa

    OECC 2013　MR1-2　2013/07

  177. A Single-Channel 1.92 Tbit/s, 64 QAM Coherent Pulse OTDM Transmission over 150 km Peer-reviewed

    D. O. Otuya, K. Kasai, T. Hirooka, M. Yoshida, M. Nakazawa

    OECC 2013　WR2-2　2013/07

  178. Extremely Higher-Order Modulation Formats Peer-reviewed

    Masataka Nakazawa, Toshihiko Hirooka, Masato Yoshida, Keisuke Kasai

    Optical Fiber Telecommunications VIB: Systems and Networks: Sixth Edition　297-336　2013/05/13

    Publisher: Elsevier Inc.

    DOI： 10.1016/B978-0-12-396960-6.00007-9 　

  179. 400 Gbit/s 256 QAM-OFDM Transmission over 720 km with a 14 bit/s/Hz Spectral Efficiency Using an Improved FDE Technique Peer-reviewed

    T. Omiya, M. Yoshida, M. Nakazawa

    Optical Fiber Communication Conference (OFC2013)　OTh4E.1　2013/03

  180. Multicore EDFA for DWDM transmission in full c-band Peer-reviewed

    Y. Tsuchida, K. Maeda, K. Watanabe, T. Ito, K. Fukuchi, M. Yoshida, Y. Mimura, R. Sugizaki, M. Nakazawa

    Optical Fiber Communication Conference (OFC2013)　JW2A.16　2013/03

  181. 400 Gbit/s 256 QAM-OFDM transmission over 720 km with a 14 bit/s/Hz spectral efficiency by using high-resolution FDE Peer-reviewed

    Tatsunori Omiya, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　21　(3)　2632-2641　2013/02

    DOI： 10.1364/OE.21.002632 　

    ISSN： 1094-4087

  182. 160 Gbit/s-300 km single-channel transmission in the 1.1 mu m band with a precise GVD and slope compensation Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　21　(4)　4303-4310　2013/02

    DOI： 10.1364/OE.21.004303 　

    ISSN： 1094-4087

  183. A Single-Channel, 1.6 Tbit/s 32 QAM Coherent Pulse Transmission Over 150 km With RZ-CW Conversion and FDE Techniques Peer-reviewed

    David Odeke Otuya, Keisuke Kasai, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa, Tokutaka Hara, Satoshi Oikawa

    2013 OPTICAL FIBER COMMUNICATION CONFERENCE AND EXPOSITION AND THE NATIONAL FIBER OPTIC ENGINEERS CONFERENCE (OFC/NFOEC)　OTh4E.4　2013

  184. Generation of 9 W, 4 kHz linewidth (C2H2)-C-13 frequency-stabilized fiber laser output with core pumped erbium-doped amplifier Peer-reviewed

    Akira Fujisaki, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka, Andmasataka Nakazawa

    2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　CW3M.1　2013

    ISSN： 2160-9020

  185. Single-channel 1.28 Tbit/s transmission over 58 km in the 1.1 μm band with wideband GVD and dispersion slope compensation Peer-reviewed

    Kengo Koizumi, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    IET Conference Publications　2013　(622)　615-617　2013

    DOI： 10.1049/cp.2013.1478 　

  186. Single-channel 1.28 Tbit/s transmission over 58 km in the 1.1 μm band with wideband GVD and dispersion slope compensation Peer-reviewed

    Kengo Koizumi, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    IET Conference Publications　2013　(622)　615-617　2013

    DOI： 10.1049/cp.2013.1478 　

  187. 512 QAM transmission over 240 km using frequency-domain equalization in a digital coherent receiver Peer-reviewed

    Yuki Koizumi, Kazushi Toyoda, Tatsunori Omiya, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　20　(21)　23383-23389　2012/10

    DOI： 10.1364/OE.20.023383 　

    ISSN： 1094-4087

  188. A 31 mW, 280 fs passively mode-locked fiber soliton laser using a high heat-resistant SWNT/P3HT saturable absorber coated with siloxane Peer-reviewed

    Takato Ono, Yuichiro Hori, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa, Junji Mata, Jun Tsukamoto

    OPTICS EXPRESS　20　(21)　23659-23665　2012/10

    DOI： 10.1364/OE.20.023659 　

    ISSN： 1094-4087

  189. Marked performance improvement of 256 QAM transmission using a digital back-propagation method Peer-reviewed

    Kazushi Toyoda, Yuki Koizumi, Tatsunori Omiya, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　20　(18)　19815-19821　2012/08

    DOI： 10.1364/OE.20.019815 　

    ISSN： 1094-4087

  190. 1024 QAM (60 Gbit/s) single-carrier coherent optical transmission over 150 km Peer-reviewed

    Yuki Koizumi, Kazushi Toyoda, Masato Yoshida, Masataka Nakazawa

    OPTICS EXPRESS　20　(11)　12508-12514　2012/05

    DOI： 10.1364/OE.20.012508 　

    ISSN： 1094-4087

  191. Nondestructive measurement of mode couplings along a multi-core fiber using a synchronous multi-channel OTDR Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    OPTICS EXPRESS　20　(11)　12530-12540　2012/05

    DOI： 10.1364/OE.20.012530 　

    ISSN： 1094-4087

  192. B-13-51 Measurement of mode couplings along a multi-core fiber using a multi-channel OTDR Peer-reviewed

    Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2012　(2)　555-555　2012/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

  193. Single-Carrier 800-Gb/s 32 RZ/QAM Coherent Transmission Over 225 km Employing a Novel RZ-CW Conversion Technique Peer-reviewed

    Keisuke Kasai, David Odeke Otuya, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　24　(5)　416-418　2012/03

    DOI： 10.1109/LPT.2011.2180373 　

    ISSN： 1041-1135

    eISSN： 1941-0174

  194. 64QAM Real-Time Coherent Transmission Using FPGA-Based Receiver Peer-reviewed

    YOSHIDA Masato, OMIYA Tatsunori, KASAI Keisuke, NAKAZAWA Masataka

    The transactions of the Institute of Electronics, Information and Communication Engineers. B　95　(3)　405-413　2012/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1344-4697

  195. 400 Gbit/s Frequency-Division-Multiplexed and Polarization-Multiplexed 256 QAM-OFDM Transmission over 400 km with a Spectral Efficiency of 14 bit/s/Hz Peer-reviewed

    T. Omiya, K. Toyoda, M. Yoshida, M. Nakazawa

    Optical Fiber Communication Conference (OFC2012)　OM2A.7　2012/03

  196. Ultrafast Coherent Optical Transmission Invited Peer-reviewed

    Masataka Nakazawa, Toshihiko Hirooka, Masato Yoshida, Keisuke Kasai

    IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS　18　(1)　363-376　2012/01

    DOI： 10.1109/JSTQE.2011.2125781 　

    ISSN： 1077-260X

    eISSN： 1558-4542

  197. Low Loss Photonic Crystal Fiber Fabricated by Slurry Casting Method Invited Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　CTh3G.1　2012

    ISSN： 2160-9020

  198. A Cesium optical atomic clock with high optical frequency stability Peer-reviewed

    Kazunari Tokuhira, Fumitaka Suzuki, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　9　(18)　1496-1503　2012

    DOI： 10.1587/elex.9.1496 　

    ISSN： 1349-2543

  199. Low Loss Photonic Crystal Fiber Fabricated by Slurry Casting Method Peer-reviewed

    Tamotsu Yajima, Jun Yamamoto, Futoshi Ishii, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　21　(25)　30500-30506　2012

    DOI： 10.1364/OE.21.030500 　

    ISSN： 2160-9020

  200. 2.56 Tbit/s/ch polarization-multiplexed DQPSK transmission over 300 km using time-domain optical Fourier transformation Peer-reviewed

    Pengyu Guan, Toshiyuki Hirano, Koudai Harako, Yutaro Tomiyama, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　19　(26)　567-573　2011/12

    DOI： 10.1364/OE.19.00B567 　

    ISSN： 1094-4087

  201. 10 GHz, 1.1 ps optical pulse generation from a regeneratively mode-locked Yb fiber laser in the 1.1 mu m band Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    OPTICS EXPRESS　19　(25)　25426-25432　2011/12

    DOI： 10.1364/OE.19.025426 　

    ISSN： 1094-4087

  202. Absolutely optical-frequency-stabilized cesium optical atomic clock Peer-reviewed

    M. Yoshida, F. Suzuki, T. Morisaki, M. Nakazawa

    17th Microoptics Conference (MOC’11)　B-2　2011/10

  203. 10 GHz, 1.1 ps pulse generation from a harmonically and regeneratively mode-locked Yb fiber laser at 1.1 μm Peer-reviewed

    K. Koizumi, M. Yoshida, T. Hirooka, M. Nakazawa

    17th Microoptics Conference (MOC’11)　H-22　2011/10

  204. Novel RZ-CW Conversion Scheme for Ultra Multi-level, High-speed Coherent OTDM Transmission Peer-reviewed

    M. Nakazawa, K. Kasai, M. Yoshida, T. Hirooka

    European Conference on Optical Communication (ECOC2011)　We.10.P1.75　2011/09

  205. “Multi” is everywhere Invited Peer-reviewed

    M. Nakazawa

    Korea-Japan Workshop on Beyond 100G　2011/06

  206. Recent Progress on Ultra-high Speed and Multi Level Coherent Transmission Invited Peer-reviewed

    T. Hirooka, K. Kasai, M. Nakazawa

    Korea-Japan Workshop on Beyond 100G　2011/06

  207. B-10-38 Real-time FPGA-based coherent optical receiver for 1 Gsymbol/s, 64 QAM transmission Peer-reviewed

    Yoshida Masato, Omiya Tatsunori, Kasai Keisuke, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2011　(2)　347-347　2011/02/28

  208. 256 QAM Digital Coherent Optical Transmission Using Raman Amplifiers Peer-reviewed

    Masato Yoshida, Seiji Okamoto, Tatsunori Omiya, Keisuke Kasai, Masataka Nakazawa

    IEICE TRANSACTIONS ON COMMUNICATIONS　E94B　(2)　417-424　2011/02

    DOI： 10.1587/transcom.E94.B.417 　

    ISSN： 0916-8516

    eISSN： 1745-1345

  209. A 10 GHz 2.5 ps Regeneratively Mode-Locked Yb Fiber Laser in the 1.1 mu m Band Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2011 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)　CMBB3　2011

    ISSN： 2160-9020

  210. Novel RZ-CW Conversion Scheme for Ultra Multi-Level, High-Speed Coherent OTDM Transmission Peer-reviewed

    Masataka Nakazawa, Keisuke Kasai, Masato Yoshida, Toshihiko Hirooka

    2011 37TH EUROPEAN CONFERENCE AND EXHIBITION ON OPTICAL COMMUNICATIONS (ECOC 2011)　19　(26)　B574-B580　2011

  211. Optical frequency-tunable Cs atomic clock with a 9.19GHz mode-hop-free fiber laser Peer-reviewed

    Takahito Morisaki, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　7　(21)　1652-1658　2010/11

    DOI： 10.1587/elex.7.1652 　

    ISSN： 1349-2543

  212. 60Gbit/s 64 QAM-OFDM coherent optical transmission with a 5.3GHz bandwidth Peer-reviewed

    Tatsunori Omiya, Seiji Okamoto, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　7　(15)　1163-1168　2010/08

    DOI： 10.1587/elex.7.1163 　

    ISSN： 1349-2543

  213. Single-Channel 400-Gb/s OTDM-32 RZ/QAM Coherent Transmission Over 225 km Using an Optical Phase-Locked Loop Technique Peer-reviewed

    Keisuke Kasai, Tatsunori Omiya, Pengyu Guan, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　22　(8)　562-564　2010/04

    DOI： 10.1109/LPT.2010.2042708 　

    ISSN： 1041-1135

  214. A 10-GHz Optoelectronic Oscillator at 1.1 mu m Using a Single-Mode VCSEL and a Photonic Crystal Fiber Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　22　(5)　293-295　2010/03

    DOI： 10.1109/LPT.2009.2038892 　

    ISSN： 1041-1135

  215. 256-QAM (64 Gb/s) Coherent Optical Transmission Over 160 km With an Optical Bandwidth of 5.4 GHz Peer-reviewed

    Masataka Nakazawa, Seiji Okamoto, Tatsunori Omiya, Keisuke Kasai, Masato Yoshida

    IEEE PHOTONICS TECHNOLOGY LETTERS　22　(3)　185-187　2010/02

    DOI： 10.1109/LPT.2009.2037238 　

    ISSN： 1041-1135

  216. 10 Gbit/s photonic crystal fiber transmissions with 1.1 μm directly-modulated single-mode VCSEL

    Kengo Koizumi, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    Optics InfoBase Conference Papers　2010

    Publisher: Optical Society of America (OSA)

    DOI： 10.1364/ofc.2010.owk3 　

    ISSN： 2162-2701

  217. Recent progress on OTDM terabit/s transmission and their future

    Toshihiko Hirooka, M. Nakazawa, M. Yoshida, K. Kasai, P. Guan, T. Hirano

    2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010　2010

  218. 256 QAM (64 Gbit/s) Coherent Optical Transmission over 160 km with an Optical Bandwidth of 5.4 GHz Peer-reviewed

    Masataka Nakazawa, Seiji Okamoto, Tatsunori Omiya, Keisuke Kasai, Masato Yoshida

    2010 CONFERENCE ON OPTICAL FIBER COMMUNICATION OFC COLLOCATED NATIONAL FIBER OPTIC ENGINEERS CONFERENCE OFC-NFOEC　OMJ5　2010

  219. 140 Gbit/s Coherent Optical Transmission over 150 km with a 10 Gsymbol/s Polarization-Multiplexed 128 QAM Signal Peer-reviewed

    Seiji Okamoto, Tatsunori Omiya, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2010 CONFERENCE ON OPTICAL FIBER COMMUNICATION OFC COLLOCATED NATIONAL FIBER OPTIC ENGINEERS CONFERENCE OFC-NFOEC　OThD5　2010

  220. Single-Channel 400 Gbit/s, OTDM-32 RZ/QAM Coherent Transmission Over 225 km Using an Optical Phase-Locked Loop Technique Peer-reviewed

    Keisuke Kasai, Tatsunori Omiya, Pengyu Guan, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2010 CONFERENCE ON OPTICAL FIBER COMMUNICATION OFC COLLOCATED NATIONAL FIBER OPTIC ENGINEERS CONFERENCE OFC-NFOEC　OThD6　2010

  221. Single-Channel 400 Gbit/s, OTDM-32 RZ/QAM Coherent Transmission Over 225 km Using an Optical Phase-Locked Loop Technique Peer-reviewed

    Keisuke Kasai, Tatsunori Omiya, Pengyu Guan, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    2010 CONFERENCE ON OPTICAL FIBER COMMUNICATION OFC COLLOCATED NATIONAL FIBER OPTIC ENGINEERS CONFERENCE OFC-NFOEC　22　(8)　562-564　2010

    DOI： 10.1109/LPT.2010.2042708 　

  222. A 10 GHz Opto-electronic Oscillator at 1.1 mu m Using a Gain-Switched InGaAs VCSEL and a Photonic Crystal Fiber Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Masataka Nakazawa

    2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS)　CMA7　2010

  223. Optical Frequency-Tunable Cs Atomic Clock with a Mode-Hop-Free Fiber Laser Peer-reviewed

    Takahito Morisaki, Masato Yoshida, Masataka Nakazawa

    2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS)　CMN2　2010

  224. A C(2)H(2) Frequency-Stabilized Laser Diode with a Linewidth of 4 kHz and Its Application to an Optical Phase-Locked Loop Peer-reviewed

    Keisuke Kasai, Masataka Nakazawa

    2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS)　CTuKK7　2010

  225. 512 QAM (54 Gbit/s) Coherent Optical Transmission over 150 km with an Optical Bandwidth of 4.1 GHz Peer-reviewed

    Seiji Okamoto, Kazushi Toyoda, Tatsunori Omiya, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2010 36TH EUROPEAN CONFERENCE AND EXHIBITION ON OPTICAL COMMUNICATION (ECOC), VOLS 1 AND 2　PD2.3　2010

    DOI： 10.1109/ECOC.2010.5621378 　

  226. 10-GHz 11.5-ps Pulse Generation From a Single-Mode Gain-Switched InGaAs VCSEL at 1.1 mu m Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　21　(22)　1704-1706　2009/11

    DOI： 10.1109/LPT.2009.2031920 　

    ISSN： 1041-1135

  227. 10Gbit/s photonic crystal fiber transmissions with 1.1 mu m directly-modulated single-mode VCSEL Peer-reviewed

    Kengo Koizumi, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　6　(22)　1615-1620　2009/11

    DOI： 10.1587/elex.6.1615 　

    ISSN： 1349-2543

  228. 10Gbit/s photonic crystal fiber transmissions with 1.1μm directly-modulated VCSEL Peer-reviewed

    KOIZUMI Kengo, HIROOKA Toshiko, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　109　(179)　51-54　2009/08/20

    ISSN： 0913-5685

  229. A passively mode-locked femtosecond soliton fiber laser at 1.5 mu m with a CNT-doped polycarbonate saturable absorber Invited Peer-reviewed

    Fumio Shohda, Takafumi Shirato, Masataka Nakazawa, Kyoji Komatsu, Toshikuni Kaino

    2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5　16　(26)　538-+　2009

    DOI： 10.1364/OE.16.021191 　

  230. C(2)H(2) absolutely optical frequency-stabilized and 40 GHz repetition-rate-stabilized, regeneratively mode-locked picosecond erbium fiber laser at 1.53 mu m Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Keisuke Kasai

    2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5　771-772　2009

  231. Delivery of an ultrastable Cs optical atomic clock using a JGN II optical test bed Peer-reviewed

    Masato Yoshida, Ikuro Kashiwamura, Toshihiko Hirooka, Masataka Nakazawa

    2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5　1557-1558　2009

  232. 24 Gbit/s, 64 QAM-OFDM Coherent Transmission with a Bandwidth of 2.5 GHz Peer-reviewed

    Tatsunori Omiya, Hiroki Goto, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2009 35TH EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)　1.3.2　2009

  233. C2H2 absolutely optical frequency-stabilized and 40 GHz repetition-rate-stabilized, regeneratively mode-locked picosecond erbium fiber laser at 1.53 mu m Invited Peer-reviewed

    Masataka Nakazawa, Keisuke Kasai, Masato Yoshida

    OPTICS LETTERS　33　(22)　2641-2643　2008/11

    DOI： 10.1364/OL.33.002641 　

    ISSN： 0146-9592

  234. 160-Gb/s 200-km Field Transmission Experiment With Large PMD Using a Time-Domain Optical Fourier Transformation Technique Invited Peer-reviewed

    Masatada Okazaki, Pengyu Guan, Toshihiko Hirooka, Masataka Nakazawa, Tetsuya Miyazaki

    IEEE PHOTONICS TECHNOLOGY LETTERS　20　(21-24)　2192-2194　2008/11

    DOI： 10.1109/LPT.2008.2006407 　

    ISSN： 1041-1135

  235. B-10-70 Frequency division multiplexed 1 Gsymbol/s, 64 QAM coherent optical transmission with a spectral efficiency of 8.6bit/s/Hz Peer-reviewed

    Goto Hiroki, Omiya Tatsunori, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2008　(2)　213-213　2008/09/02

    DOI： 10.1109/ECOC.2008.4729160 　

  236. A lambda/4-Shifted Distributed-Feedback Laser Diode With a Fiber Ring Cavity Configuration Having an OSNR of 85 dB and a Linewidth of 7 kHz Invited Peer-reviewed

    Ho Thi Quynhanh, Akihito Suzuki, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　20　(17-20)　1578-1580　2008/09

    DOI： 10.1109/LPT.2008.928848 　

    ISSN： 1041-1135

  237. Polarization and frequency division multiplexed 1Gsymbol/s, 64 QAM coherent optical transmission with 8.6bit/s/Hz spectral efficiency over 160km Invited Peer-reviewed

    Hiroki Goto, Masato Yoshida, Tatsunori Omiya, Keisuke Kasai, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　5　(18)　776-781　2008/09

    DOI： 10.1587/elex.5.776 　

    ISSN： 1349-2543

  238. New scheme for independently stabilizing the repetition rate and optical frequency of a laser using a regenerative mode-locking technique Invited Peer-reviewed

    NAKAZAWA Masataka, YOSHIDA Masato

    IEICE technical report　108　(194)　39-44　2008/08/21

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We have succeeded in achieving independent control of the repetition rate and optical frequency of a pulse laser by employing a regenerative mode-locking technique. By adopting a voltage-controlled microwave phase shifter or an optical delay line in a regenerative feedback loop, we can control the repetition rate of the laser without directly disturbing the optical frequencies. We show experimentally how this independent control can be realized by employing a 40GHz harmonically and regeneratively mode-locked fiber laser.

  239. An ultrastable Cs optical atomic clock with a regeneratively mode-locked fiber laser and an optically pumped Cs gas cell Peer-reviewed

    T. Hirayama, M. Yoshida, M. Nakazawa, K. Hagimoto, T. Ikegami

    CLEO/QELS 2007　Postdeadline Paper CPDB11　2008/05

  240. Scheme for independently stabilizing the repetition rate and optical frequency of a laser using a regenerative mode-locking technique Invited Peer-reviewed

    Masataka Nakazawa, Masato Yoshida

    OPTICS LETTERS　33　(10)　1059-1061　2008/05

    DOI： 10.1364/OL.33.001059 　

    ISSN： 0146-9592

  241. A mode-locked laser-type optical atomic clock with an optically pumped Cs gas cell Peer-reviewed

    T. Hirayama, M. Yoshida, M. Nakazawa, K. Hagimoto, T. Ikegami

    Asia-Pacific Microwave Photonics 2007　D-38　2008/04

  242. Frequency Division Multiplexed 1 Gsymbol/s, 64 QAM Coherent Optical Transmission with a Spectral Efficiency of 8.6 bit/s/Hz Peer-reviewed

    Masato Yoshida, Hiroki Goto, Tatsunori Omiya, Keisuke Kasai, Masataka Nakazawa

    2008 34TH EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)　2008

  243. The use of a Nyquist filter for reducing an optical signal bandwidth in a coherent QAM optical transmission Peer-reviewed

    Keisuke Kasai, Jumpei Hongo, Hiroki Goto, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　5　(1)　6-10　2008/01

    DOI： 10.1587/elex.5.6 　

    ISSN： 1349-2543

  244. 64 and 128 coherent QAM optical transmission over 150 km using frequency-stabilized laser and heterodyne PLL detection Invited Peer-reviewed

    Masato Yoshida, Hiroki Goto, Keisuke Kasai, Masataka Nakazawa

    OPTICS EXPRESS　16　(2)　829-840　2008/01

    DOI： 10.1364/OE.16.000829 　

    ISSN： 1094-4087

  245. Polarization-multiplexed 1 Gsymbol/s, 128 QAM (14 Gbit/s) coherent optical transmission over 160 km using a 1.4 GHz Nyquist filter Peer-reviewed

    Hiroki Goto, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2008 CONFERENCE ON OPTICAL FIBER COMMUNICATION/NATIONAL FIBER OPTIC ENGINEERS CONFERENCE, VOLS 1-8　133-135　2008

  246. 10 GHz regeneratively mode-locked semiconductor optical amplifier fiber ring laser and its linewidth characteristics Peer-reviewed

    Masato Yoshida, Atsushi Ono, Masataka Nakazawa

    OPTICS LETTERS　32　(24)　3513-3515　2007/12

    DOI： 10.1364/OL.32.003513 　

    ISSN： 0146-9592

    eISSN： 1539-4794

  247. Optical Fiber Transmission of Standard Signals Using Optical Combs Peer-reviewed

    NAKAZAWA Masataka, HIROOKA Toshihiko, YOSHIDA Masato

    The Review of Laser Engineering　35　(10)　649-653　2007/10/15

    Publisher: The Laser Society of Japan

    DOI： 10.2184/lsj.35.649 　

    ISSN： 0387-0200

    More details Close

    Recently, the delivery of frequency standards using optical combs through optical fiber networks has become an important subject. When we transmit optical combs through an optical fiber network, it is very important to investigate the distortion in the power spectrum of the longitudinal modes that occurs during the transmission. In this paper, we describe the spectrum deformation of the longitudinal mode that occurs during long-haul transmission through a dispersion-shifted fiber, when we use a 10 GHz mode-locked fiber laser with a linewidth as narrow as 1 kHz as the signal source. We found that the deformation of the longitudinal mode power spectrum occurs mainly at the tail of the spectrum, and the linewidth broadening increases in proportion to the transmission distance. The main reason for the linewidth broadening was the phase fluctuation of the optical fiber caused by temperature fluctuation.

  248. A l/4-shifted distributed feedback semiconductor fiber ring laser with an OSNR of 85 dB and a linewidth of 7 kHz Peer-reviewed

    A. Suzuki, H. T. Quynhanh, M. Yoshida, M. Nakazawa

    European Conference on Optical Communication (ECOC 2007)　1.4.2　2007/09

  249. An ultralow noise and narrow linewidth lambda/4-shifted DFB Er-doped fiber laser with a ring cavity configuration Peer-reviewed

    Akihito Suzuki, Youhei Takahashi, Masato Yoshida, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　19　(17-20)　1463-1465　2007/09

    DOI： 10.1109/LPT.2007.902697 　

    ISSN： 1041-1135

  250. Regeneratively mode-locked fiber laser with a repetition rate stability of 4.9X10(-15) using a hydrogen maser phase-locked loop Peer-reviewed

    Masato Yoshida, Toru Hirayama, Masataka Nakazawa, Ken Hagimoto, Takeshi Ikegami

    OPTICS LETTERS　32　(13)　1827-1829　2007/07

    DOI： 10.1364/OL.32.001827 　

    ISSN： 0146-9592

  251. 1 Gsymbol/s, 64 QAM coherent optical transmission with a spectral efficiency of 8 bit/s/Hz using a Nyquist filter Peer-reviewed

    K. Kasai, J. Hongo, H. Goto, M. Yoshida, M. Nakazawa

    OECC/IOOC 2007　Postdeadline Paper PD1-1　2007/07

  252. 10 GHz regeneratively mode-locked SOA fiber ring laser and its linewidth characteristics Peer-reviewed

    M. Yoshida, A. Ono, M. Nakazawa

    OECC2007　13C4-2　2007/07

  253. Mode-hop-free, optical frequency tunable 40-GHz mode-locked fiber laser Peer-reviewed

    Masato Yoshida, Keisuke Kasai, Masataka Nakazawa

    IEEE JOURNAL OF QUANTUM ELECTRONICS　43　(7-8)　704-708　2007/07

    DOI： 10.1109/JQE.2007.901289 　

    ISSN： 0018-9197

    eISSN： 1558-1713

  254. Mode-locked laser-type optical atomic clock with an optically pumped Cs gas cell Peer-reviewed

    Toru Hirayama, Masato Yoshida, Masataka Nakazawa, Ken Hagimoto, Takeshi Ikegami

    OPTICS LETTERS　32　(10)　1241-1243　2007/05

    DOI： 10.1364/OL.32.001241 　

    ISSN： 0146-9592

  255. 1-Gsymbol/s 64-QAM coherent optical transmission over 150 km Peer-reviewed

    Jumpei Hongo, Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    IEEE PHOTONICS TECHNOLOGY LETTERS　19　(9-12)　638-640　2007/05

    DOI： 10.1109/LPT.2007.894944 　

    ISSN： 1041-1135

    eISSN： 1941-0174

  256. A CW, polarization-maintaining lambda/4-shifted DFB Er-doped fiber laser at 1.54 mu m Peer-reviewed

    Akihito Suzuki, Youhei Takahashi, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　4　(8)　251-257　2007/04

    DOI： 10.1587/elex.4.251 　

    ISSN： 1349-2543

  257. B-10-69 1 Gsymbol/s, 64 coherent QAM optical transmission over 150 km with a spectral efficiency of 3 bit/sHz Peer-reviewed

    Hougo Jumpei, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2007　(2)　408-408　2007/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

    DOI： 10.1109/OFC.2007.4348615 　

  258. Polarization-multiplexed 1 Gsymbol/s, 64 QAM (12 Gbit/s) coherent optical transmission over 150 km with an optical bandwidth of 2 GHz Peer-reviewed

    M. Nakazawa, J. Hongo, K. Kasai, M. Yoshida

    Fiber Communication Conference (OFC 2007)　Postdeadline Paper PDP26　2007/03

  259. Optical phase-locked loop for coherent transmission over 500km using heterodyne detection with fiber lasers Peer-reviewed

    Keisuke Kasai, Jumpei Hongo, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　4　(3)　77-81　2007/02

    DOI： 10.1587/elex.4.77 　

    ISSN： 1349-2543

  260. Ultra-stable regeneratively mode-locked laser as an opto-electronic microwave oscillator and its application to optical metrology Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka

    IEICE TRANSACTIONS ON ELECTRONICS　E90C　(2)　443-449　2007/02

    DOI： 10.1093/ietele/e90-c.2.443 　

    ISSN： 0916-8524

    eISSN： 1745-1353

  261. Optical phase-locked loop for coherent transmission over 500 km

    Koisuke Kasai, Masato Yoshida, Masataka Nakazawa

    OFC/NFOEC 2007 - Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007　2007

    Publisher: IEEE Computer Society

    DOI： 10.1109/ofc.2007.4348436 　

  262. A C2H2 frequency-stabilized erbium-doped fiber laser and its application to coherent communication Peer-reviewed

    Masato Yoshida, Keisuke Kasai, Jumpei Hongo, Masataka Nakazawa

    FIBER LASERS IV: TECHNOLOGY, SYSTEMS, AND APPLICATIONS　6453　6453-85　2007

    DOI： 10.1117/12.714489 　

    ISSN： 0277-786X

  263. Optical phase-locked loop for coherent transmission over 500 km using heterodyne detection with fiber lasers Peer-reviewed

    Keisuke Kasai, Jumpei Hongo, Masato Yoshida, Masataka Nakazawa

    IEICE Electronics Express　4　(3)　77-81　2007

    DOI： 10.1587/elex.4.77 　

    ISSN： 1349-2543

  264. A mode-hop-free, frequency-tunable 40 GHz mode-locked fiber laser Peer-reviewed

    Masato Yshida, Keisuke Kasai, Masataka Nakazawa

    OFC/NFOEC 2007 - Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007　OTuF3　2007

    DOI： 10.1109/OFC.2007.4348785 　

  265. An Ultrastable Cs Optical Atomic Clock with a 9.1926-GHz Regeneratively Mode-Locked Fiber Laser Peer-reviewed

    HIRAYAMA Toru, YAKABE Masatsugu, YOSHIDA Masato, NAKAZAWA Masataka, KOGA Yasuki, HAGIMOTO Ken

    The IEICE transactions on electronics C　J90-C　(12)　977-987　2007

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

  266. Performance improvement of an acetylene (C2H2) frequency-stabilized fiber laser Peer-reviewed

    Keisuke Kasai, Akihito Suzuki, Masato Yoshida, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　3　(22)　487-492　2006/11

    DOI： 10.1587/elex.3.487 　

    ISSN： 1349-2543

  267. Ultra-Broadband Dispersion Measurement of Photonic Crystal Fiber with Pico-Second Streak Camera and Group-Delay-Free Supercontinuum Peer-reviewed

    OIKAWA Yosuke, HASEGAWA Hideaki, HIROOKA Toshihiko, YOSHIDA Masato, NAKAZAWA Masataka

    The IEICE transactions on electronics C　89　(7)　450-457　2006/07/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

    More details Close

    通研インポート200703

  268. 20 Msymbol/s, 64 and 128 QAM coherent optical transmission over 525 km using heterodyne detection with frequency-stabilised laser Peer-reviewed

    M. Nakazawa, M. Yoshida, K. Kasai, J. Hongou

    ELECTRONICS LETTERS　42　(12)　710-712　2006/06

    DOI： 10.1049/el:20060646 　

    ISSN： 0013-5194

  269. Polymer saturable absorber materials in the 1.5 mu m band using poly-methyl-methacrylate and polystyrene with single-wall carbon nanotubes and their application to a femtosecond laser Peer-reviewed

    M Nakazawa, S Nakahara, T Hirooka, M Yoshida

    OPTICS LETTERS　31　(7)　915-917　2006/04

    DOI： 10.1364/OL.31.000915 　

    ISSN： 0146-9592

  270. 10Gb/s transmission over 5 km at 850nm using single-mode photonic crystal fiber, single-mode VCSEL, and Si-APD Peer-reviewed

    Hideaki Hasegawa, Yosuke Oikawa, Masato Yoshida, Toshihiko Hirooka, Masataka Nakazawa

    IEICE ELECTRONICS EXPRESS　3　(6)　109-114　2006/03

    DOI： 10.1587/elex.3.109 　

    ISSN： 1349-2543

  271. An acetylene ((C2H2)-C-13) stabilized single-polarization fiber laser Peer-reviewed

    Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS　89　(10)　9-17　2006

    DOI： 10.1002/ecjb.20235 　

    ISSN： 8756-663X

  272. 10 Gb/s transmission over 3 km at 850 nm using single-mode photonic crystal fiber, single-mode VCSEL, and Si-APD Peer-reviewed

    Hideaki Hasegawa, Yosuke Oikawa, Toshihiko Hirooka, Masato Yoshida, Masataka Nakazawa

    2006 OPTICAL FIBER COMMUNICATION CONFERENCE/NATIONAL FIBER OPTIC ENGINEERS CONFERENCE, VOLS 1-6　1822-1824　2006

  273. Measurements of longitudinal linewidth and relative intensity noise in ultrahigh-speed mode-locked semiconductor lasers Peer-reviewed

    K Haneda, M Yoshida, H Yokoyama, Y Ogawa, M Nakazawa

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS　89　(2)　28-36　2006

    DOI： 10.1002/ecjb.20185 　

    ISSN： 8756-663X

  274. Polymer saturable absorber materials in 1.5 mu m band using PMMA and PS with single-wall carbon nanotubes Peer-reviewed

    Masataka Nakazawa, Seiji Nakahara, Toshihiko Hirooka, Masato Yoshida, Toshikuni Kaino, Kyoji Komatsu

    2006 OPTICAL FIBER COMMUNICATION CONFERENCE/NATIONAL FIBER OPTIC ENGINEERS CONFERENCE, VOLS 1-6　2154-+　2006

  275. A (C2H2)-C-13 frequency-stabilized, polarization-maintained 1.54 mu m erbium fiber ring laser with a new feedback system Peer-reviewed

    Keisuke Kasai, Masato Yoshida, Masataka Nakazawa

    2006 OPTICAL FIBER COMMUNICATION CONFERENCE/NATIONAL FIBER OPTIC ENGINEERS CONFERENCE, VOLS 1-6　866-868　2006

  276. Characteristics of CPT signals of Cs-D1 and Cs-D2 lines Peer-reviewed

    K. Hagimoto, T. Hirayama, K. Watanabe, T. Ikegami, S. Ohshima, M. Yoshida, M. Nakazawa

    Workshop on Chirp Scale Atomic Clock: Status and Potentiality　38751　2006

    More details Close

    通研ＤＢインポート

  277. 10 Gb/s x 4 channel WDM transmission over 3 km in the 800 nm region using photonic crystal fibers Peer-reviewed

    H. Hasegawa, Y. Oikawa, T. Hirooka, M. Yoshida, K. Suzuki, Y. Inoue, M. Nakazawa

    European Conference on Optical Communication (ECOC 2006)　We4.5.4　2006

    More details Close

    通研インポート200703

  278. A 1.54 #Gmu#GRm 13C2H2 frequency-stabilized, single-polarization fiber ring laser Peer-reviewed

    K. Kasai, M. Yoshida, M. Nakazawa

    European Optical Society Annual Meeting 2006, Topical Meeting on Extreme Optics (TOM 2)　94-95　2006

    More details Close

    通研インポート200703

  279. An ultra-low noise and narrow linewidth λ/4-shifted DFB Er-doped fiber laser with a ring configuration Peer-reviewed

    Akihito Suzuki, Youhei Takahashi, Masato Yoshida, Masataka Nakazawa

    2006 European Conference on Optical Communications Proceedings, ECOC 2006　Th2.3.2　2006

    DOI： 10.1109/ECOC.2006.4800962 　

  280. 20 Msymbol/s, 128 QAM coherent Optical transmission over 500 km using heterodyne detection with frequency-stabilized laser Peer-reviewed

    Masataka Nakazawa, Masato Yoshida, Keisuke Kasai, Jumpei Hongou

    2006 European Conference on Optical Communications Proceedings, ECOC 2006　Mo4.2.2　2006

    DOI： 10.1109/ECOC.2006.4800895 　

  281. Observation of Optimum Air-Hole Tapering of Splicing between a Conventional Fiber and a Photonic Crystal Fiber and Analysis of Reduction of Fresnel Reflection Peer-reviewed

    HASEGAWA Hideaki, KIKEGAWA Manabu, YOSHIDA Masato, HIROOKA Toshihiko, NAKAZAWA Masataka

    The IEICE transactions on electronics C　88　(10)　779-787　2005/10/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

    More details Close

    通研ＤＢインポート

  282. Microwave Frequency Tuning Characteristics of an Opto-Microwave Oscillator Made of Fiber Laser and Its Application to Ramsey Fringe Observation of Cs Atoms Peer-reviewed

    YAKABE Masatsugu, NITO Ko, YOSHIDA Masato, NAKAZAWA Masataka

    The IEICE transactions on communications B　88　(9)　1829-1836　2005/09/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1344-4697

    More details Close

    通研ＤＢインポート

  283. Acetylene (^<13>C_2H_2) Stabilized Single-Polarization Fiber Laser Peer-reviewed

    KASAI Keisuke, YOSHIDA Masato, NAKAZAWA Masataka

    The IEICE transactions on electronics C　88　(9)　708-715　2005/09/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

    More details Close

    通研ＤＢインポート

  284. Ultrastable cesium atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser Peer-reviewed

    M Yakabe, K Nito, M Yoshida, M Nakazawa, Y Koga, K Hagimoto, T Ikegami

    OPTICS LETTERS　30　(12)　1512-1514　2005/06

    DOI： 10.1364/OL.30.001512 　

    ISSN： 0146-9592

  285. Linewidth and relative intensity noise measurements of longitudinal modes in ultrahigh-speed mode-locked laser diodes Peer-reviewed

    K Haneda, M Yoshida, M Nakazawa, H Yokoyama, Y Ogawa

    OPTICS LETTERS　30　(9)　1000-1002　2005/05

    DOI： 10.1364/OL.30.001000 　

    ISSN： 0146-9592

    eISSN： 1539-4794

  286. C-4-27 An ultrastable Cs optical atomic clock with a laser type opto-microwave oscillator Peer-reviewed

    Yakabe M., Hirayama T., Yoshida M., Nakazawa M., Koga Y., Hagimoto K., Ikegami T.

    Proceedings of the IEICE General Conference　2005　(1)　334-334　2005/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

    More details Close

    通研ＤＢインポート

  287. Measurements of Longitudinal Linewidth and Relative Intensity Noise in Ultrahigh-Speed Mode-Locked Semiconductor Lasers Peer-reviewed

    HANEDA Kentaro, YOSHIDA Masato, YOKOYAMA Hiroyuki, OGAWA Yoh, NAKAZAWA Masataka

    The IEICE transactions on electronics C　88　(3)　161-168　2005/03/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

    More details Close

    通研ＤＢインポート

  288. A new ultrastable cesium optical atomic clock with a 9.1926-GHz regeneratively mode-locked fiberlaser Peer-reviewed

    M Yakabe, K Nito, M Yoshida, M Nakazawa, Y Koga, K Hagimoto, T Ikegami

    ULTRAFAST PHENOMENA XIV　79　831-833　2005

    ISSN： 0172-6218

  289. Optimization of a 40 GHz regeneratively and harmonically mode-locked fiber laser under PLL operation and its longitudinal mode characteristics Peer-reviewed

    M Yoshida, T Yaguchi, S Harada, M Nakazawa

    ULTRAFAST PHENOMENA XIV　79　765-767　2005

    ISSN： 0172-6218

  290. Measurement of optical carrier spectrum deformation in high-speed pulse transmission Peer-reviewed

    K Osawa, K Haneda, T Hirooka, M Yoshida, S Waiyapot, M Nakazawa

    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS　998-1000　2005

    DOI： 10.1109/CLEOPR.2005.1569851 　

  291. A (C2H2)-C-13 frequency-stabilized, polarization-maintained erbium fiber ring laser with no frequency modulation Peer-reviewed

    K Kasai, M Yoshida, M Nakazawa, K Shiota, S Masuda

    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS　295-296　2005

    DOI： 10.1109/CLEOPR.2005.1569492 　

  292. Observation of optimum air-hole tapering of splicing between conventional fiber and photonic crystal fiber and analysis of reduction in Fresnel reflection Peer-reviewed

    H Hasegawa, M Kikegawa, M Yoshida, T Hirooka, M Nakazawa

    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS　345-346　2005

    DOI： 10.1109/CLEOPR.2005.1569517 　

  293. Ultra-broadband dispersion measurement of photonic crystal fiber with pico-second streak camera and group-delay-free supercontinuum Peer-reviewed

    Y Oikawa, H Hasegawa, M Yoshida, T Hirooka, M Nakazawa

    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS　337-339　2005

    DOI： 10.1109/CLEOPR.2005.1569514 　

  294. A C2H2 frequency-stabilized, single-polarization fiber laser Peer-reviewed

    K. Kasai, M. Yoshida, M. Nakazawa

    NMIJ-BIPM Workshop on the Impact of Information Technology in Metrology　2005

    More details Close

    通研ＤＢインポート

  295. An ultrastable PLL mode-locked fiber laser with a hydrogen maser clock Peer-reviewed

    M Yoshida, T Hirayama, M Yakabe, M Nakazawa, Y Koga, K Hagimoto

    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS　1027-1028　2005

    DOI： 10.1109/CLEOPR.2005.1569865 　

  296. An ultrastable Cs optical atomic clock with a 9.1926-GHz low-drift regeneratively mode-locked fiber laser Peer-reviewed

    T Hirayama, M Yakabe, M Yoshida, M Nakazawa, Y Koga, K Hagimoto

    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS　1025-1026　2005

    DOI： 10.1109/CLEOPR.2005.1569864 　

  297. A C2H2 frequency-stabilized, polarization-maintained erbium fiber ring laser with no frequency modulation Peer-reviewed

    K. Kasai, M. Yoshida, M. Nakazawa

    30th European Conference on Optical Communication　Th1.3.5　2004/09

  298. A 40 GHz regeneratively and harmonically mode-locked erbium-doped fiber laser and its longitudinal-mode characteristics Peer-reviewed

    M Yoshida, T Yaguchi, S Harada, M Nakazawa

    IEICE TRANSACTIONS ON ELECTRONICS　E87C　(7)　1166-1172　2004/07

    ISSN： 0916-8524

    eISSN： 1745-1353

  299. Measurements of Longitudinal Linewidths of 10 GHz, Picosecond Mode-locked Erbium-Doped Fiber Lasers Using a Heterodyne Detection Method Peer-reviewed

    CHOI Samuel, YOSHIDA Masato, NAKAZAWA Masataka

    The Transactions of the Institute of Electronics, Information and Communication Engineers C　86　(10)　1054-1062　2003/10/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

  300. Observation of Huge Fresnel Reflection at a Splicing Point between a Photonic Crystal Fiber and a Conventional Fiber and Its Suppression Peer-reviewed

    YOSHIDA Masato, KIKEGAWA Manabu, NISHIMURA Naoya, NAKAZAWA Masataka

    The Transactions of the Institute of Electronics, Information and Communication Engineers C　86　(9)　1007-1016　2003/09/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1345-2827

  301. Longitudinal linewidth measurements of 10GHz, picosecond harmonically and regeneratively mode-locked erbium-doped fiber lasers using a heterodyne detection method Peer-reviewed

    Choi Samuel, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2003　(1)　324-324　2003/03/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

  302. PMD measurement based on delayed self-heterodyne OFDR and experimental comparison with ITU-T round robin measurements Peer-reviewed

    N Zou, M Yoshida, Y Namihira, H Ito

    ELECTRONICS LETTERS　38　(3)　115-116　2002/01

    DOI： 10.1049/el:20020073 　

    ISSN： 0013-5194

  303. A new technique for measuring dispersion of optical fibers using a frequency-shifted feedback fiber laser. Part 1: Measurement of group velocity dispersion Peer-reviewed

    M Yoshida, T Miyamoto, K Nakamura, H Ito

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS　85　(2)　1-7　2002

    DOI： 10.1002/ecja.1070 　

    ISSN： 8756-6621

  304. A mode-locked frequency-shifted feedback fiber laser Peer-reviewed

    M. Yoshida, M. Fujimoto, M. Nakazawa, H. Ito

    2001 Conference on Lasers and Electro-Optics　CWA50　2001/05

  305. A new method for measurement of group velocity dispersion of optical fibers by using a frequency-shifted feedback fiber laser Peer-reviewed

    M Yoshida, K Nakamura, H Ito

    IEEE PHOTONICS TECHNOLOGY LETTERS　13　(3)　227-229　2001/03

    DOI： 10.1109/68.914329 　

    ISSN： 1041-1135

  306. Measurement of polarization mode dispersion based on optical frequency domain reflectometry technique Peer-reviewed

    Nianyu Zou, Masato Yoshida, Yoshinori Namihira, Hiromasa Ito

    2001 Optical Fiber Communication Conference　ThA1　(2)　648-648　2001/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

  307. Novel measurement method of PMD in single mode fiber based on optical frequency domain reflectometry technique Peer-reviewed

    Nianyu Zou, Masato Yoshida, Tsutomu Aoyama, Hiromasa Ito

    Proceedings of SPIE - The International Society for Optical Engineering　4579　208-215　2001

    DOI： 10.1117/12.444892 　

    ISSN： 0277-786X

  308. Average atmosphere temperature measurement by a Frequency-Shifted Feedback laser Peer-reviewed

    N Kibayashi, T Hara, M Yoshida, K Nakamura, H Ito

    OPTICAL REMOTE SENSING OF THE ATMOSPHERE AND CLOUDS II　4150　322-329　2001

    DOI： 10.1117/12.416973 　

    ISSN： 0277-786X

  309. Novel PMD measurement method based on OFDR using a frequency-shifted feedback fiber laser Peer-reviewed

    M. Yoshida, T. Miyamoto, Nianyu Zou, K. Nakamura, H. Ito

    Optics Express　9　(4)　207-211　2001

    Publisher: Optical Society of America (OSA)

    DOI： 10.1364/OE.9.000207 　

    ISSN： 1094-4087

  310. A New Technique for Measuring Dispersion of Optical Fibers Using a Frequency-shifted Feedback Fiber Laser: Measurement of Group Velocity Dispersion Peer-reviewed

    YOSHIDA Masato, MIYAMOTO Toshiyuki, NAKAMURA Koichiro, ITO Hiromasa

    The Transactions of the Institute of Electronics,Information and Communication Engineers B　83　(11)　1608-1613　2000/11/25

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1344-4697

  311. Measurement of polarization mode dispersion of optical with a frequency-shifted feedback laser Peer-reviewed

    Zou N., Yoshida M., Nakamura K., Ito H.

    Proceedings of the Society Conference of IEICE　2000　(2)　438-438　2000/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  312. Long distance measurement with high spatial resolution by optical frequency domain reflectometry using a frequency-shifted feedback fiber laser Peer-reviewed

    M. Yoshida, K. Nakamura, H. Ito

    2000 Conference on Lasers and Electro-Optics　319-320　2000/05

  313. Optical frequency domain ranging by a frequency-shifted feedback laser Peer-reviewed

    K Nakamura, T Hara, M Yoshida, T Miyahara, H Ito

    IEEE JOURNAL OF QUANTUM ELECTRONICS　36　(3)　305-316　2000/03

    DOI： 10.1109/3.825877 　

    ISSN： 0018-9197

  314. Effect of Group Velicity Dispersion of Optical Fiber on Optical Frequency Domain Reflectometry

    Masato Yoshida, Koichiro Nakamura, Hiromasa Ito

    Technical Digest "Conference on Lasers and Electro-Optics '99"　388　1999/05

  315. Improvement of a measurement range of optical frequency domain reflectometry by using a frequency-shifted feedback Peer-reviewed

    K. Nakamura, T. Hara, M. Yoshida, H. Ito

    1999 Conference on Lasers and Electro-Optics　CMD8　1999/05

  316. Study of Frequency-Shifted Feedback Fiber Laser

    YOSHIDA Masato

    The Record of Electrical and Communication Engineering Conversation Tohoku University　68　(1)　311　1999

  317. Frequency-Shifted Feedback Fiber Laser. Peer-reviewed

    Yoshida Masato, NAKAMURA Koichiro, ITO Hiromasa

    The Review of Laser Engineering　27　(7)　490-494　1999

    Publisher: The Laser Society of Japan

    DOI： 10.2184/lsj.27.490 　

    ISSN： 0387-0200

    More details Close

    In the frequency-shifted feedback laser (FSF laser), a frequency shift is imposed on an intracavity light field by feedback of the first order diffracted light of an acousto-optic modulator (AOM). Here we report the first observation of a chirped frequency comb output from this type of laser with erbium-doped fiberas a gain medium, and investigate its application to optical reflectometry. The spatial resolution is demonstrated to be 1.5 mm.

  318. Effect group velocity dispersion of optical on optical frequency domain reflectometry Peer-reviewed

    M. Yoshida, T. Miyamoto, K. Nakamura, H. Ito

    1999 International Topical Workshop on Contemporary Photonic Technologies　Wep7　1999/01

  319. A new technique of optical ranging by a frequency-shifted feedback laser Peer-reviewed

    K Nakamura, T Miyahara, M Yoshida, T Hara, H Ito

    IEEE PHOTONICS TECHNOLOGY LETTERS　10　(12)　1772-1774　1998/12

    DOI： 10.1109/68.730498 　

    ISSN： 1041-1135

  320. Erbium- doped fiber laser with a frequency-shifted feedback; Oscillation characteristics and application to optical to optical reflectometry Peer-reviewed

    M. Yoshida, K. Nakamura, T. Miyahara, H. Ito

    1998 European Conference on Lasers and Electro-Optics　CWE3　1998/09

Show all ︎Show first 5

Misc. 209

  1. オールデジタル方式による16 QAM-4,000 kmコヒーレントナイキストパルス伝送

    芹川 武貴, 吉田 真人, 廣岡 俊彦, 葛西 恵介, 中沢 正隆

    2025年電子情報通信学会総合大会　B-10B-29　2025/03

  2. IF 125 GHzにおける108 Gbit/s-64 QAM信号のSMF 10 km、無線10 mフルコヒーレント伝送

    城市 知輝, 葛西 恵介, 吉田 真人, 廣岡 俊彦, 中沢 正隆

    2025年電子情報通信学会総合大会　B-10B-18　2025/03

  3. 100 Gbit/s-class fully coherent mobile fronthaul transmission towards next-generation radio access networks

    葛西恵介, 城市知輝, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告(Web)　124　(331(CS2024 78-89))　2025

    ISSN： 2432-6380

  4. Quantum Noise Stream Cipher by Combining Mathematical and Physical Cryptographies

    吉田真人, 中沢正隆

    日本セキュリティ・マネジメント学会誌(Web)　39　(1)　2025

    ISSN： 2434-5504

  5. 108 Gbit/s-64 QAM transmission over 10 km-SMF and 70 m wirelessly with a fully coherent method at IF-125 GHz

    城市知輝, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告(Web)　125　(59(OCS2025 11-22))　2025

    ISSN： 2432-6380

  6. 108 Gbit/s-64 QAM fully coherent transmission over a 10 km-SMF and 10 m wirelessly at 125 GHz-IF

    城市知輝, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2025　2025

    ISSN： 1349-144X

  7. Application of optical communication and measurement technologies for multipoint field observations using compact absolute gravimeters

    新谷錫人, 葛西恵介, 吉田真人, 中沢正隆

    日本測地学会講演会要旨　144th　2025

  8. 126 Gbit/s-128 QAM fully coherent transmission over a 10 km-SMF and 10 m wirelessly using a direct sampling method

    佐久間勇誠, 佐久間勇誠, 渡部新, 渡部新, 城市知輝, 城市知輝, 葛西恵介, 吉田真人, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2025　2025

    ISSN： 1349-144X

  9. IF 30 GHz における 108 Gbit/s-64 QAM 信号の SMF 10 km、無線 10 mフルコヒーレント伝送

    渡部 新, 城市 知輝, 葛西 恵介, 吉田 真人, 廣岡 俊彦, 中沢 正隆

    2024年電子情報通信学会ソサイエティ大会　B-10B-23　2024/09

  10. 時間領域マスキングを用いた3次元量子雑音ストリーム暗号

    吉田 真人, 葛西 恵介, 廣岡 俊彦, 中沢 正隆

    2024年電子情報通信学会ソサイエティ大会　B-10B-09　2024/09

  11. 6つのLPモードを有するフューモードファイバ中のGAWBS雑音特性

    吉田 哲也, 別府 翔平, 吉田 真人, 葛西 恵介, 廣岡 俊彦, 中沢 正隆

    2024年電子情報通信学会ソサイエティ大会　B-10A_B-13-27　2024/09

  12. 1-Tb/s/λ PS-32QAM, 1,600 km 総伝送容量 21.5 Tb/s コヒーレントナイキスト光パルス伝送

    石川碧人, 別府翔平, 芹川武貴, 吉田真人, 廣岡俊彦, 中沢 正隆

    2024年電子情報通信学会総合大会　B10B-31　2024/03

  13. 28 GHz帯光モバイルフロントホール用フルコヒーレント伝送における注入同期型ヘテロダイン方式とセルフヘテロダイン方式の性能比較

    白幡晃一, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆, 東 右一郎, 小林敏幸

    2024年電子情報通信学会総合大会　B10B-6　2024/03

  14. エルミートガウスパルスを用いた時間領域モード多重コヒーレント伝送

    中沢正隆, 吉田真人, 廣岡俊彦

    2024年電子情報通信学会総合大会　B10B-10　2024/03

  15. Fully coherent optical and wireless transmission in the 28 GHz band by using an injection-locked carrier frequency converter

    白幡晃一, 白幡晃一, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆, 東右一郎, 小林敏幸

    電子情報通信学会技術研究報告(Web)　123　(330(OCS2023 57-66))　2024

    ISSN： 2432-6380

  16. 108 Gbit/s-64 QAM fully coherent transmission over a 10 km-SMF and 10 m wirelessly in 30 GHz-IF

    渡部新, 渡部新, 城市知輝, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2024　2024

    ISSN： 1349-144X

  17. 28 GHz帯マイクロストリップアレイアンテナを用いた16 Gbits-256 QAM信号のSMF10 km、無線10 mフルコヒーレント伝送

    白幡晃一, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    2023年電子情報通信学会ソサイエティ大会　B10-11　2023/09

  18. フューモードファイバ中のGAWBS雑音特性

    吉田真人, 平井孝明, 葛西恵介, 廣岡俊彦, 中沢正隆

    2023年電子情報通信学会ソサイエティ大会　B13-2　2023/09

  19. MCFの無反射型FIFO技術

    吉田真人, 中沢正隆

    電子情報通信学会EXAT研究会　2023/08

  20. Coherently-linked optical and wireless transmission by using a 28 GHz band microstrip antenna

    葛西恵介, 佐藤大晟, 佐藤大晟, 白幡晃一, 白幡晃一, 吉田真人, 廣岡俊彦, 中沢正隆, 東右一郎, 小林敏幸

    電子情報通信学会技術研究報告(Web)　122　(378(AP2022 197-233))　2023

    ISSN： 2432-6380

  21. A proposal of radio IQ direct digital coherent transmission in mobile fronthaul

    葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆, 松尾英範, 高橋領

    電子情報通信学会大会講演論文集(CD-ROM)　2023　2023

    ISSN： 1349-144X

  22. Coherently-linked optical and wireless transmission using a 28 GHz band phased array microstrip antenna

    佐藤大晟, 佐藤大晟, 葛西恵介, 白幡晃一, 白幡晃一, 吉田真人, 廣岡俊彦, 中沢正隆, 東右一郎, 小林敏幸

    電子情報通信学会大会講演論文集(CD-ROM)　2023　2023

    ISSN： 1349-144X

  23. Application of Digital Coherent Optical Transmission Technology for Beyond 5G Mobile Fronthaul

    葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会誌　106　(6)　2023

    ISSN： 0913-5693

  24. Beyond5G/6Gでの活用が期待されるマルチコアファイバ〈2〉マルチコアファイバを収容した光海底ケーブルの評価技術の開発

    吉田真人, 中沢正隆

    光アライアンス　34　(12)　2023

    ISSN： 0917-026X

  25. アナログおよびデジタルDEMUX方式による160 Gbaudコヒーレント光ナイキストパルス信号の復調特性の比較

    吉田真人, 木村光佑, 葛西恵介, 廣岡俊彦, 中沢正隆

    2022年電子情報通信学会ソサイエティ大会　2022/09

  26. GAWBS Phase-Noise Correlation Characteristics Between Cores in 19-Core Fiber

    佐藤耕造, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2022　2022

    ISSN： 1349-144X

  27. Evaluation technique of mode-coupling along a multi-core fiber with a multi-channel OTDR

    吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2022　2022

    ISSN： 1349-144X

  28. Performance comparison between injection-locking type carrier frequency conversion and self-heterodyne detection methods in coherently-linked optical and wireless transmission

    佐藤大晟, 佐藤大晟, 白幡晃一, 白幡晃一, 葛西恵介, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2022　2022

    ISSN： 1349-144X

  29. Performance comparison of injection-locked carrier frequency conversion and self-heterodyne detection methods in cohelently-linked optical and wireless transmission

    佐藤大晟, 佐藤大晟, 白幡晃一, 白幡晃一, 葛西恵介, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会技術研究報告(Web)　121　(320(OCS2021 33-40))　2022

    ISSN： 2432-6380

  30. Single-channel 1.28 Tbit/s Optical Nyquist Pulse Transmission over 3000 km

    渡邊碧, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  31. 64 Gbit/s, 256 QAM coherently-linked optical and wireless transmission at 61 GHz-band using an injection-locked carrier frequency converter

    佐藤大晟, 佐藤大晟, 葛西恵介, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  32. GAWBS Noise Correlation Characteristics Between Cores in Four-Core Fiber

    佐藤耕造, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  33. Study on Chromatic Dispersion Dependence of GAWBS noise

    佐藤耕造, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    光通信システムシンポジウムプログラム&講演予稿集(CD-ROM)　35th　2021

  34. R&D on high-capacity multi-core fiber transmission systems

    森田逸郎, 相馬大樹, 釣谷剛宏, 吉田真人, 八坂洋, 長谷川健美, 林哲也, 高坂繁弘, 前田幸一, 杉崎隆一, 井上貴則, 竹下仁士, 高畠武敏, 小林哲也

    電子情報通信学会技術研究報告(Web)　120　(388(PN2020 41-63))　2021

    ISSN： 2432-6380

  35. Intra-Cavity Loss Dependence of Modulation Bandwidth Characteristics in Hybrid Modulation Semiconductor Lasers

    内山香, 内山香, 横田信英, 吉田真人, 八坂洋

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  36. Performance comparison between Fabry-Perot LD based- and ECLD based-injection-locking circuits

    葛西恵介, 管貴志, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  37. Evaluation of Wide-band Small Signal Response in Hybrid Modulation Laser

    島卓未, 島卓未, 吉田真人, 横田信英, 八坂洋

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  38. Recent Progress in Carrier Down-Conversion Devices Between Optical Communication and Beyond 5G Wireless Communication

    佐藤昭, 佐藤昭, 中嶋大, 中嶋大, 西村和樹, 西村和樹, 細谷友崇, 細谷友崇, 細谷友崇, 岩月勝美, 末光哲也, 末光哲也, 葛西恵介, 葛西恵介, 吉田真人, 吉田真人, 尾辻泰一, 尾辻泰一

    電子情報通信学会技術研究報告(Web)　121　(309(ED2021 48-61))　2021

    ISSN： 2432-6380

  39. Study on Chromatic Dispersion Dependence of GAWBS Noise

    佐藤耕造, 管貴志, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  40. 12.8 Tbit/s (1.28 Tbit/s/ch x 10) OTDM-WDM Transmission of PDM-DQPSK Optical Nyquist Pulses over 1500 km

    渡邊碧, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  41. BER performance improvement of ultrahigh-speed coherent Nyquist pulse transmission using low-nonlinearity, dispersion-compensated transmission line with chirped FBG and LCoS

    木村光佑, 木村光佑, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告(Web)　121　(18(OFT2021 1-11))　2021

    ISSN： 2432-6380

  42. Precise and Wideband Compensation of WDM Inter-Channel Cross-Phase Modulation Noise Using Injection Locking

    管貴志, 佐藤耕造, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  43. Low-Nonlinearity, Dispersion-Compensated Transmission Line with a Chirped Fiber Bragg Grating and LCoS and Its Application to Ultrahigh-Speed Coherent Nyquist Pulse Transmission

    岩屋太郎, 木村光佑, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2021　2021

    ISSN： 1349-144X

  44. Toward optical and wireless convergence with coherently-linked access network

    廣岡俊彦, 葛西恵介, 吉田真人, 中沢正隆

    電子情報通信学会技術研究報告(Web)　120　(341(SR2020 47-59))　2021

    ISSN： 2432-6380

  45. Study on chromatic dispersion dependence of GAWBS noise

    佐藤耕造, 管貴志, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告(Web)　120　(309(OCS2020 27-39))　2021

    ISSN： 2432-6380

  46. 12.8 Tbit/s (1.28 Tbit/s/ch x 10) OTDM-WDM Transmission of PDM-DQPSK Optical Nyquist Pulses over 1500 km

    渡邊碧, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告(Web)　120　(309(OCS2020 27-39))　2021

    ISSN： 2432-6380

  47. Next Generation C-RAN Mobile Fronthaul Using On-line Bi-directional 256 QAM WDM Coherent Transmission

    管貴志, 吉田真人, 葛西恵介, 廣岡俊彦, 岩月勝美, 中沢正隆

    電子情報通信学会技術研究報告　119　(366(OCS2019 65-77)(Web))　2020

    ISSN： 0913-5685

  48. Effect of GAWBS Depolarization Noise on Digital Coherent Optical Transmission

    竹節直也, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2020　2020

    ISSN： 1349-144X

  49. A proposal on optical-wireless mobile fronthaul for advanced 5G

    中沢正隆, 葛西恵介, 吉田真人, 廣岡俊彦, 岩月勝美

    電子情報通信学会大会講演論文集(CD-ROM)　2020　2020

    ISSN： 1349-144X

  50. Single-channel 15.3 Tbit/s, 64 QAM coherent Nyquist pulse transmission over 150 km

    木村光佑, 吉田真人, 岩屋太郎, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2020　2020

    ISSN： 1349-144X

  51. 10 Tbit/s QAM quantum noise stream cipher coherent transmission over 160 km

    吉田真人, 管貴志, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2020　2020

    ISSN： 1349-144X

  52. Experimental and theoretical analyses of GAWBS phase noise in multi-core fibers for digital coherent transmission

    吉田真人, 竹節直也, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告(Web)　120　(140(OCS2020 4-7))　2020

    ISSN： 2432-6380

  53. 160 Gbit/s, 256 QAM bidirectional coherent transmission for mobile fronthaul without backward Rayleigh scattering interference

    葛西恵介, 吉田真人, 廣岡俊彦, 岩月勝美, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2020　2020

    ISSN： 1349-144X

  54. Experimental and theoretical analyses of GAWBS noise in multi-core fiber

    吉田真人, 竹節直也, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2020　2020

    ISSN： 1349-144X

  55. GAWBS noise influence for digital coherent transmission and its fiber dependence

    竹節直也, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    光通信システムシンポジウムプログラム&講演予稿集(CD-ROM)　33rd　2019

  56. Sub-Picosecond Optical Switch over Entire C-Band by Using Nonlinear Optical Loop Mirror

    平田綾也, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会技術研究報告　119　(93(OCS2019 10-19)](Web))　2019

    ISSN： 0913-5685

  57. GAWBS noise characteristics in digital coherent transmission in various optical fibers

    竹節直也, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告　119　(93(OCS2019 10-19)](Web))　2019

    ISSN： 0913-5685

  58. 50.4 Tbit/s, L-band 480 ch-WDM, 128 QAM-160 km Digital Coherent Optical Transmission Using an Injection-locked Homodyne Receiver

    管貴志, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告　119　(93(OCS2019 10-19)](Web))　2019

    ISSN： 0913-5685

  59. 通信波長帯光源を用いた小型絶対重力計TAG-1の運用と系統誤差評価

    新谷昌人, 葛西恵介, 吉田真人, 中沢正隆, 田村良明, 坪川恒也

    日本測地学会講演会要旨　132nd　2019

  60. 次世代モバイルフロントホール用256QAMオンライン双方向コヒーレント伝送

    吉田真人, 管貴志, 葛西恵介, 廣岡俊彦, 岩月勝美, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  61. リアルタイム偏波多重256~512QAMデジタルコヒーレント光伝送

    吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  62. 256QAM WDMオンライン双方向コヒーレント伝送を用いた次世代C-RANモバイルフロントホール

    管貴志, 吉田真人, 葛西恵介, 廣岡俊彦, 岩月勝美, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  63. デジタルコヒーレント光伝送における各種ファイバのGAWBS雑音特性

    竹節直也, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  64. 注入同期法を用いた200Gbit/s,10Gsymbol/s-1024QAM160kmデジタルコヒーレント光伝送

    葛西恵介, 岡本聖司, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  65. 高精度光位相制御技術を用いた超多値QAMコヒーレント光伝送

    吉田真人, 葛西恵介, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  66. 50.4Tbit/s,L-band WDM128QAM-160kmコヒーレント光伝送

    管貴志, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  67. 非線形光ループミラーを用いたフルCバンドサブピコ秒光スイッチ

    平田綾也, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2019　2019

    ISSN： 1349-144X

  68. 10ペタビット級光伝送実験の成功 (特集 空間分割多重光通信技術の進展)

    相馬 大樹, 若山 雄太, 別府 翔平, 角田 聖也, 釣谷 剛宏, 林 哲也, 永島 拓志, 鈴木 雅人, 吉田 真人, 葛西 恵介, 中沢 正隆, 高橋 英憲, 五十嵐 浩司, 森田 逸郎, 鈴木 正敏

    O plus E : Optics + electronics　40　(6)　724-728　2018/09

    Publisher: アドコム・メディア

    ISSN： 0911-5943

  69. Measurement of mode coupling along a multi-core fiber/a few mode fiber using a multi-channel OTDR

    37　(8)　78-83　2018/08

    Publisher: オプトロニクス社

    ISSN： 0286-9659

  70. 導波音響波型ブリルアン散乱(GAWBS)の観測とコヒーレントQAM伝送におけるそのデジタル補償

    中沢正隆, 吉田真人, 寺山雅樹, 岡本聖司, 葛西恵介, 廣岡俊彦

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  71. 単一チャンネル7.68Tbit/s-150km,64QAMコヒーレントナイキストパルス伝送

    新田純平, 木村光佑, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  72. 4096QAM(72Gbit/s)-160kmディジタルコヒーレント光伝送

    寺山雅樹, 岡本聖司, 葛西恵介, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  73. 光注入同期法を用いた次世代モバイルフロントホール用160Gbit/s,256QAMデジタルコヒーレント伝送

    葛西恵介, WANG Yixin, 吉田真人, 廣岡俊彦, 岩月勝美, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  74. 注入同期法を用いた12bit/s/Hz,58.2Tbit/s,256QAM-160km CバンドWDM伝送

    管貴志, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  75. 単一チャネル10.2Tbit/s-300km光ナイキストパルス伝送

    平田綾也, WANG Jianping, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  76. GAWBS位相雑音補償による1024QAMコヒーレント光伝送におけるエラーフロアの抑制

    吉田真人, 竹節直也, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  77. PS-4096QAM信号と1024QAM信号の160km伝送特性比較

    岡本聖司, 岡本聖司, 寺山雅樹, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  78. 空間分割多重光通信技術の進展 10ペタビット級光伝送実験の成功

    相馬大樹, 若山雄太, 別府翔平, 角田聖也, 釣谷剛宏, 林哲也, 永島拓志, 鈴木雅人, 吉田真人, 葛西恵介, 中沢正隆, 高橋英憲, 五十嵐浩司, 五十嵐浩司, 森田逸郎, 鈴木正敏

    O plus E　(463)　2018

    ISSN： 0911-5943

  79. 光ナイキストパルスを用いた単一チャネル10Tbit/s級超高速伝送

    廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2018　2018

    ISSN： 1349-144X

  80. Single-channel 10.2 Tbit/s Optical Nyquist Pulse Transmission Over 300 km

    平田綾也, WANG Jianping, 廣岡俊彦, 吉田真人, 中沢正隆

    電子情報通信学会技術研究報告　118　(238(OFT2018 13-51)(Web))　2018

    ISSN： 0913-5685

  81. 12 bit/s/Hz, 58.2 Tbit/s, 256 QAM-160 km C-band WDM Transmission Using an Injection Locking Technique

    管貴志, 葛西恵介, 吉田真人, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告　118　(238(OFT2018 13-51)(Web))　2018

    ISSN： 0913-5685

  82. Observation of GAWBS Noise and Development of its Compensation Technique in Digital Coherent Optical Transmission

    竹節直也, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会技術研究報告　118　(238(OFT2018 13-51)(Web))　2018

    ISSN： 0913-5685

  83. 光直交振幅変調による量子暗号通信

    平野琢也, 並木亮, 中沢正隆, 吉田真人, 廣岡俊彦, 葛西恵介

    応用物理学会春季学術講演会講演予稿集(CD-ROM)　64th　2017

    ISSN： 2758-4704

  84. 単一チャネル3.84Tbit/s,64QAMコヒーレントナイキストパルス信号の150km伝送

    新田純平, 木村光佑, 吉田真人, 葛西恵介, 廣岡俊彦, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2017　2017

    ISSN： 1349-144X

  85. 光注入同期を用いた42.3Tbit/s,C-band WDM64QAM-160kmコヒーレント伝送

    管貴志, 葛西恵介, 吉田真人, 中沢正隆

    電子情報通信学会大会講演論文集(CD-ROM)　2017　2017

    ISSN： 1349-144X

  86. New Optical Phase-Locking System Based on Mode-Locked Fiber Laser for 640 Gbaud Coherent Nyquist QAM Transmission

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2017　(0)　22-22　2017

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2017.0_22 　

  87. High Spectral Efficient Transmission with Digital Coherent Ultra-multilevel QAM Format

    45　(12)　466-471　2016/12

    Publisher: 日本光学会

    ISSN： 0389-6625

  88. 光ファイバーネットワークを利用した地殻変動および津波計測

    中沢正隆, 吉田真人, 葛西恵介

    光技術コンタクト　54　(12)　22-31　2016/12

    Publisher: 光学工業技術協会

    ISSN： 0913-7289

  89. B-10-52 320 Gbit/s, 256 QAM Coherent Optical Transmission over 160 km with an LD-based Injection-locked Homodyne Receiver

    Wang Yixin, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2016　(2)　345-345　2016/03/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

  90. C-4-12 295 mW output, HCN frequency-stabilized CW erbium fiber ring laser

    Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2016　(1)　216-216　2016/03/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

  91. B-10-38 Real-time adaptive 4-64 QAM, 20-60 Gbit/s quantum noise stream cipher transmission

    Nakazawa Masataka, Yoshida Masato, Hirooka Toshihiko, Kasai Keisuke

    Proceedings of the IEICE General Conference　2016　(2)　331-331　2016/03/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

  92. Preliminary experiment on 4096 QAM coherent optical transmission at 1.5 Gsymbol/s over 160 km

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2016　(0)　7-7　2016

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2016.0_7 　

  93. 45.12 Tbit/s, 235 ch-WDM 64 QAM Coherent Transmission over 160 km with an Injection Locked Homodyne Receiver

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2016　(0)　6-6　2016

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2016.0_6 　

  94. B-10-45 448 Gbit/s, 32 Gbaud 128 QAM coherent transmission over 150 km with a potential spectral efficiency of 10.7 bit/s/Hz

    Kasai Keisuke, Wang Yixin, Otuya David Odeke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2015　(2)　209-209　2015/08/25

    Publisher: The Institute of Electronics, Information and Communication Engineers

  95. B-10-50 1024 QAM, 7-core (60 Gbit/s x 7) fiber transmission over 55 km with an aggregate spectral efficiency of 109 bit/s/Hz

    Yoshida Masato, Beppu Shohei, Kasai Keisuke, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2015　(2)　214-214　2015/08/25

    Publisher: The Institute of Electronics, Information and Communication Engineers

  96. B-10-57 QAM quantum noise stream cipher using digital coherent optical transmission

    Nakazawa Masataka, Yoshida Masato, Hirooka Toshihiko, Kasai Keisuke

    Proceedings of the Society Conference of IEICE　2015　(2)　221-221　2015/08/25

    Publisher: The Institute of Electronics, Information and Communication Engineers

  97. 10 GHz, 0.95 ps coherent optical pulse source based on 1.55 μm HCN frequency-stabilized mode-locked fiber laser

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2015　(0)　2-2　2015

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2015.0_2 　

  98. Recent development of ultra-multilevel digital coherent QAM transmission

    33　(12)　40-44　2014/12

    Publisher: オプトロニクス社

    ISSN： 0286-9659

  99. B-10-43 2048 QAM (66 Gbit/s) Digital Coherent Optical Transmission over 150 km

    Beppu Shohei, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2014　(2)　411-411　2014/03/04

    Publisher: The Institute of Electronics, Information and Communication Engineers

  100. 2048 QAM coherent optical transmission over 150 km

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2014　(0)　13-13　2014

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2014.0_13 　

  101. 1.28 Tbit/s-58 km single-channel transmmission at 1.1μm

    Koizumi Kengo, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2013　(2)　240-240　2013/09/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

  102. 光多値化技術とさらなる周波数利用効率向上に向けて (特集 光ファイバー通信の新たなブレークスルーへ向けて)

    中沢 正隆, 廣岡 俊彦, 吉田 真人

    O plus E : Optics・Electronics　35　(8)　836-841　2013/08

    Publisher: アドコム・メディア

    ISSN： 0911-5943

  103. TK-3-7 Optical Transmission Technologies for Enhancing the Resilience of Information and Communication Networks

    Morita Itsuro, Yoshikane Noboru, Tsuritani Takehiro, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2013　(2)　"SSS-30"-"SSS-31"　2013/03/05

    Publisher: The Institute of Electronics, Information and Communication Engineers

  104. B-10-26 AStudy on the Optimization of 7-core Multicore Erbium-doped Fiber Optical Amplifier

    Tsuchida Yukihiro, Maeda Koichi, Watanabe Kengo, Ito Toshiharu, Fukuchi Kiyoshi, Yoshida Masato, Mimura Yu, Sugizaki Ryuichi, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2013　(2)　357-357　2013/03/05

    Publisher: The Institute of Electronics, Information and Communication Engineers

  105. ペタビットを目指すマルチコア光ファイバ技術 III 多値伝送実現に向けたマルチコア光ファイバの大コア化とクロストーク評価技術

    今村勝徳, 杉崎隆一, 吉田真人, 中沢正隆

    ITUジャーナル(Web)　43　(11)　2013

    ISSN： 2434-9712

  106. A 1.5 µm Passively Mode-locked Fiber Soliton Laser with a Graphene-doped PVA Saturable Absorber

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2013　(0)　23-23　2013

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2013.0_23 　

  107. B-10-34 Marked performance improvement of 256 QAM transmission using a digital back-propagation method

    Toyoda Kazushi, Koizumi Yuki, Omiya Tatsunori, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2012　(2)　216-216　2012/08/28

    Publisher: The Institute of Electronics, Information and Communication Engineers

  108. B-10-35 Performance improvement of 512 QAM transmission using frequency-domain equalization

    Omiya Tatsunori, Koizumi Yuki, Toyoda Kazushi, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2012　(2)　217-217　2012/08/28

    Publisher: The Institute of Electronics, Information and Communication Engineers

  109. B-10-62 1.1 μm, 160 Gbit/s OTDM transmission over 30 km

    Koizumi Kengo, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2012　(2)　244-244　2012/08/28

    Publisher: The Institute of Electronics, Information and Communication Engineers

  110. B-10-67 1024 QAM (60 Gbit/s) optical coherent transmission over 150 km

    Koizumi Yuki, Toyoda Kazushi, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2012　(2)　249-249　2012/08/28

    Publisher: The Institute of Electronics, Information and Communication Engineers

  111. Performance improvement of optical frequency stabilized Cs optical atomic clock

    TOKUHIRA Kazunari, SUZUKI Fumitaka, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report. Component parts and materials　112　(182)　21-25　2012/08/16

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We have proposed a Cs optical atomic clock, which generates a standard microwave clock signal with an optical pulse. The clock source uses a regenerative mode-locked fiber laser (MLFL) as a microwave oscillator and an optically pumped Cs gas cell as a frequency standard. In this report, the output pulse width was shortened from 7.1 to 3.4 ps by employing a phase modulator instead of an intensity modulator as a mode-locker. The optical frequency stability for an averaging time of 100 s was also improved from 1.8 x 10^<-11> to 6.3 x 10^<-12> by precisely controlling the laser cavity temperature.

  112. 1.07μm passively mode-locked ytterbium-doped fiber laser with SWNT/PMMA saturable absorber

    YOSHIDA Masato, HORI Yuichiro, HIROOKA Toshihiko, NAKAZAWA Masataka

    IEICE technical report. Component parts and materials　112　(182)　83-86　2012/08/16

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Single-wall carbon nanotubes (SWNT) have received considerable attention as a nonlinear optical material for ultrashort lasers and optical switch devices because of their attractive features such as ultrafast saturable absorption (SA) effects with a recovery time of faster than 1 ps. The SA wavelength depends on the tube diameter. We previously reported an SWNT polymer material that used polymethylmethacrylate (PMMA) and applied it to a passively mode-locked Er fiber laser for 171 fs pulse generation at 1.55 μm. In this report, we describe a mode-locked Yb-doped fiber laser for femtosecond pulse generation at 1.1 μm realized by using an SWNT/PMMA wafer in the cavity. By optimizing the cavity configuration as a dispersion-managed soliton laser, we obtained a 543 fs, 15.1 MHz pulse train.

  113. Increase of Output Power of Passively Mode-Locked Fiber Laser with a SWNT

    ONO Takato, HORI Yuichiro, YOSHIDA Masato, HIROOKA Toshihiko, NAKAZAWA Masataka, MATA Junji, TSUKAMOTO Jun

    IEICE technical report. Component parts and materials　112　(182)　87-90　2012/08/16

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We have demonstrated a passively mode-locked fiber laser with SWNT-based saturable absorbers made by uniformly dispersing SWNTs into polymer such as poly methyl methacrylate, or by depositing SWNTs on the optical fiber end. However, the output power of the lasers is limited to less than 10 mW due to relatively low tolerance to optical damage of these SWNT-based saturable absorbers. In this work, we fabricated a SWNT saturable absorber with a substantial increase in the optical damage threshold by sealing SWNT with siloxane which has a high heat resistance. By installing this saturable absorber in a passively mode-locked fiber laser, a 31 mW, 280 fs ultrashort pulse was successfully generated.

  114. 32 RZ/QAM coherent optical transmission employing an RZ-CW conversion technique

    KASAI Keisuke, OTUYA David Odeke, YOSHIDA Masato, HIROOKA Toshihiko, NAKAZAWA Masataka

    Technical report of IEICE. OCS　112　(152)　13-18　2012/07/19

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Coherent optical time division multiplexing (OTDM) transmission with a multi-level modulation format has attracted a lot of attention as a ultra-high speed and highly spectral-efficient optical transmission system. However, in the conventional coherent OTDM, it is difficult to demodulate an ultra-high speed, multi-level RZ data signal with a high signal to noise ratio due to input optical power limitation of coherent detection circuits. Recently, we proposed a demodulation scheme by using an RZ-CW conversion scheme in a coherent receiver, in which the transmitted coherent RZ data are OTDM demultiplexed and converted into a data signal on a CW carrier. In this paper, we demonstrate an advantage of the scheme with 10 Gsymbol/s, 4- and 8-OTDM 32 RZ/QAM demodulation experiments. Furthermore, we have successfully transmitted a polarization multiplexed, 10 Gsymbol/s, 32 RZ/QAM (800 Git/s) data signal over 225 km by using this conversion scheme.

  115. Demultiplexing of 160Gbit/s OTDM signal using a nonlinear optical loop mirror at 1.1μm

    KOIZUMI Kengo, HIROOKA Toshihiko, YOSHIDA Masato, NAKAZAWA Masataka

    Technical report of IEICE. OCS　112　(86)　47-52　2012/06/14

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    With the increasing demand for ultrahigh capacity optical networks, it has been increasingly important to exploit new transmission bandwidths beyond the 1.55 and 1.31μm bands. The 1.1μm region is expected to provide an ultrawide transmission band because a wideband ytterbium (Yb)-doped fiber amplifiers (YDFA) are available. In this talk, we describe a multiplexer and demultiplexer using a nonlinear optical loop mirror (NOLM), and demonstrate the generation and demultiplexing of a 160 Gbit/s optical time-division multiplexed (OTDM) signal using a 10 GHz mode-locked Yb fiber laser in the 1.1μm wavelength region.

  116. C-4-30 A 1070 nm passively mode-locked ytterbium-doped fiber soliton laser with a SWNT/PMMA saturable absorber

    Hori Yuichiro, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2012　(1)　281-281　2012/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

  117. B-10-33 400 Gbit/s Frequency-Division-Multiplexed and Polarization-Multiplexed 256 QAM-OFDM Transmission over 400 km

    Omiya Tatsunori, Toyoda Kazushi, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2012　(2)　356-356　2012/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

  118. B-10-54 Single-channel 800 Gbit/s, 32 RZ/QAM coherent transmission employing an RZ-CW conversion technique

    Kasai Keisuke, Odeke Otuya David, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2012　(2)　377-377　2012/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

  119. B-10-70 Demultiplexing of 160 Gbit/s OTDM signal using a nonlinear optical loop mirror at 1.1μm

    Koizumi Kengo, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2012　(2)　393-393　2012/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

  120. BI-7-8 512 QAM ultra-multilevel digital coherent optical transmission

    Koizumi Yuki, Toyoda Kazushi, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2011　(1)　"SS-67"-"SS-68"　2011/08/30

    Publisher: The Institute of Electronics, Information and Communication Engineers

  121. Development of FPGA-based real-time receiver for 64 QAM coherent signals

    YOSHIDA Masato, OMIYA Tatsunori, KASAI Keisuke, NAKAZAWA Masataka

    IEICE technical report　111　(122)　7-12　2011/07/04

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We demonstrate the first real-time coherent optical transmission of a 1 Gsymbol/s, 64 QAM data signal. The real-time coherent receiver consists of four 1 GS/s analog-to-digital converters (ADC) and a field-programmable gate array (FPGA) implementation. The bit error rate (BER) performance obtained with the real-time receiver is the same as that obtained with an off-line digital signal processor (DSP). This result indicates that the phase of the IF signal and the data clock timing are precisely controlled without any DSP compensations in our real-time coherent transmission system. As a result, an error free performance (BER < 1 x 10<-12>) has been achieved under a back-to-back condition.

  122. Frequency Division Multiplexing 64 QAM-OFDM (420 Gb/s) transmission over 160 km

    OMIYA Tatsunori, TOYODA Kazushi, KASAI Keisuke, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　111　(122)　93-98　2011/07/04

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We have demonstrated 64QAM-OFDM coherent optical transmission with a C_2H_2 frequency-stabilized fiber laser and an optical phase-locked loop (OPLL) circuit. In this report, we describe experimental result of 7ch-frequency-division-multiplexed and polarization-multiplexed 5 Gsymbol/s 64 QAM-OFDM (420 Gb/s) transmission. After 160 km transmission, we applied compensation for impairments due to fiber nonlinearity by using back propagation method and improved the bit error rate (BER) performance. As a result, a BER below the forward error correction (FEC) limit and a spectral efficiency as high as 10.4 b/s/Hz were successfully demonstrated.

  123. B-10-39 512 QAM (54 Gbit/s) coherent optical transmission over 150 km

    Okamoto Seiji, Toyoda Kazushi, Omiya Tatsunori, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2011　(2)　348-348　2011/02/28

    Publisher: The Institute of Electronics, Information and Communication Engineers

  124. Performance improvement of 10Gsymbol/s, 64 QAM coherent optical transmission by using back propagation method of nonlinear Schrodinger equation

    TOYODA Kazushi, OKAMOTO Seiji, OMIYA Tatsunori, YOSHIDA Masato, HIROOKA Toshihiko, NAKAZAWA Masataka

    IEICE technical report　110　(392)　67-72　2011/01/20

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We have demonstrated 64〜512 QAM coherent optical transmission using a C_2H_2 frequency-stabilized fiber laser and an OPLL circuit. In such a ultra multi-level transmission, compensation for impairments due to fiber dispersion and nonlinearity plays a very important role. As a highly precise compensation scheme, a back propagation method of the nonlinear Schrodinger equation has been proposed. We applied this scheme to a single-polarization, 10 Gsymbol/s, 64 QAM transmission and demonstrated the impairment compensation both numerically and experimentally.

  125. B-10-79 Performance improvement of 10 Gsymbol/s, 64QAM coherent optical transmission by using back propagation method of nonlinear Schrodinger equation

    Toyoda Kazushi, Okamoto Seiji, Omiya Tatsunori, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2010　(2)　266-266　2010/08/31

    Publisher: The Institute of Electronics, Information and Communication Engineers

  126. Single-channel 400Gbit/s, OTDM-32 RZ/QAM coherent transmission over 225km

    KASAI Keisuke, OMIYA Tatsunori, GUAN Pengyu, YOSHIDA Masato, HIROOKA Toshihiko, NAKAZAWA Masataka

    IEICE technical report　110　(94)　1-6　2010/06/17

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Coherent optical time division multiplexing (OTDM) transmission with a multi-level modulation format based on digital signal processing (DSP) has attracted a lot of attention with a view to expanding the capacity per channel of wavelength division multiplexing (WDM) transmission systems. This transmission system can overcome the speed and bandwidth limitations of electrical components such as A/D and D/A converters and realize ultrahigh-speed coherent transmission by using a multi-level amplitude and phase-modulated coherent RZ pulse and the OTDM. However, in a conventional coherent OTDM system, the optical phase between an RZ data pulse and a local oscillator are not phase-locked. Therefore, it is difficult to realize a coherent OTDM transmission with high multiplicity. In this work, we demonstrated a multi-level coherent OTDM transmission with a high-precision optical phase-locked loop (OPLL) technique by using optical comb generation circuits. 400 Gbit/s data (polarization-multiplexed, 10 Gsymbol/s, 4-OTDM 32 RZ/QAM) were successfully transmitted over 225 km with a bit error rate performance below the forward error correction (FEC) limit. We also realized a 320 Gbit/s-450 km transmission with an OTDM 16 RZ/QAM scheme.

  127. B-10-62 Optical phase-locked loop for coherent OTDM transmission with an optical comb technique

    Yoshida Masato, Kasai Keisuke, Omiya Tatsunori, Guan Pengyu, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2010　(2)　400-400　2010/03/02

    Publisher: The Institute of Electronics, Information and Communication Engineers

  128. B-10-82 Single-channel 400Gbit/s, OTDM-32 RZ/QAM coherent transmission over 225 km

    Kasai Keisuke, Omiya Tatsunori, Guan Pengyu, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2010　(2)　420-420　2010/03/02

    Publisher: The Institute of Electronics, Information and Communication Engineers

  129. B-10-83 10 Gsymbol/s, 128 QAM (140 Gbit/s) coherent optical transmission over 150km

    Okamoto Seiji, Omiya Tatsunori, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2010　(2)　421-421　2010/03/02

    Publisher: The Institute of Electronics, Information and Communication Engineers

  130. B-10-84 256 QAM (64 Gbit/s) coherent optical transmission over 160km

    Nakazawa Masataka, Okamoto Seiji, Omiya Tatsunori, Kasai Keisuke, Yoshida Masato

    Proceedings of the IEICE General Conference　2010　(2)　422-422　2010/03/02

    Publisher: The Institute of Electronics, Information and Communication Engineers

  131. C-4-1 A 10GHz opto-electronic oscillator at 1.1μm using a single-mode VCSEL and a photonic crystal fiber

    Koizumi Kengo, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2010　(1)　252-252　2010/03/02

    Publisher: The Institute of Electronics, Information and Communication Engineers

  132. B-10-40 Polarization and frequency division multiplexed 1 Gsymbol/s, 64 QAM coherent optical transmission with 8.6 bit/s/Hz spectral efficiency over 160 km

    Goto Hiroki, Omiya Tatsunori, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2009　(2)　220-220　2009/09/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

  133. B-10-41 5 Gsymbol/s, 64 QAM-OFDM(30 Gbit/s) coherent optical transmission

    Omiya Tatsunori, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2009　(2)　221-221　2009/09/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

  134. C-4-21 10 GHz-11.5 ps pulse generation form a gain-switched VCSEL at 1.1 μm

    Koizumi Kengo, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2009　(1)　259-259　2009/09/01

    Publisher: The Institute of Electronics, Information and Communication Engineers

  135. A 0.4GHz ultranarrow FBG optical filter with 30-dB side lobe suppression

    MORI Anne, KASAI Keisuke, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　109　(179)　63-68　2009/08/20

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A fiber Bragg grating (FBG) is an attractive optical filter device because of its narrow wavelength selectivity, low loss, compactness, and low cost. Therefore, it is useful for applications such as coherent optical communication systems, optical sensing and optical metrological standard. These applications require both a narrow bandwidth and a high side lobe suppression ratio. We have already demonstrated a 1.3GHz ultranarrow FBG filter with a side lobe suppression ratio of 13dB. In this paper, we report a 0.4GHz FBG filter with a side lobe suppression ratio as high as 30dB by combining a uniform FBG and a λ/4 shifted FBG.

  136. 10GHz-11.5ps pulse generation from a gain-switched VCSEL at 1.1μm

    KOIZUMI Kengo, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　109　(174)　89-92　2009/08/13

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Vertical cavity surface emitting laser (VCSEL) is an attractive light source because of its low threshold, single longitudinal-mode operation, and high-speed modulation. In addition, the VCSEL is suitable for short pulse generation because of the short photon life time due to the very short cavity. Therefore, a high-speed picosecond pulse source can be realized with a simple configuration by using a gain-switched VCSEL. In this paper, we describe 10GHz pulse generation from gain-switched InGaAs VCSEL at 1.1μm. The shortest pulse pulse width of 11.5ps was obtained after chirp compensation.

  137. Optical frequency-stabilized and 40GHz repetition-rate-stabilized, regeneratively mode-locked pulse laser

    YOSHIDA Masato, KASAI Keisuke, NAKAZAWA Masataka

    IEICE technical report　109　(174)　97-102　2009/08/13

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Ultrastable mode-locked pulse lasers operating in the GHz region have been receiving a lot of attention with respect to their application to both ultrahigh-speed optical transmission, micro-photonics and optical metrology. In particular, control of the laser frequency is very important for optical coherent communication and optical metrology applications. In this paper, we have succeeded in the simultaneous stabilization of the optical frequency and repetition rate of a 40GHz regeneratively mode-locked picosecond erbium-doped fiber ring laser. The optical frequency was locked to the molecular absorption of C_2H_2 in the 1.5μm band and the repetition rate was stabilized to a 40GHz synthesizer by using a microwave phase-locked loop.

  138. Cs optical atomic clock with a mode-hop-free fiber laser

    MORISAKI Takahito, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　109　(174)　103-108　2009/08/13

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Recently, delivery technique of standards through optical fiber networks has been receiving a lot of attention with respect to their application to frequency standard and measurement. As such optical signal source, we have developed a Cs optical atomic clock that uses a regeneratively mode-locked fiber laser (MLFL) as a microwave oscillator and an optically pumped Cs gas cell as a frequency standard. The Cs optical atomic clock can emit stable transform-limited picosecond pulses with a repetition rate of 9.1926GHz (Cs resonance). However, it was difficult to control the optical frequency of the optical output pulse from the Cs atomic clock because of the MLFL mode-hopping. In this work, we achieved mode-hop-free Cs optical atomic clock by inserting an etalon in the MLFL.

  139. 64 QAM-OFDM coherent optical transmission

    OMIYA Tatsunori, GOTO Hiroki, KASAI Keisuke, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　109　(31)　1-6　2009/05/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Recently, Orthogonal Frequency Division Multiplexing (OFDM) system, that was originally developed in wireless communication, has been intensively studied in optical communication. The multi-carrier transmission of low-speed orthogonal subcarriers enables us to improve both spectral efficiency and dispersion tolerance by adopting high-level subcarrier modulation formats and employing coherent detection in OFDM. So far, 1 Tb/s per channel OFDM transmission and OFDM optical coherent transmission with 32 QAM subcarrier modulation have been reported. In this report, we realize, for the first time, QAM subcarrier modulation up to 64 levels using 128 subcarriers and demonstrate OFDM transmission over a 160km.

  140. C-3-3 A 0.4 GHz ultranarrow FBG optical filter with 30-dB side lobe suppression

    Mori Anne, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2009　(1)　154-154　2009/03/04

    Publisher: The Institute of Electronics, Information and Communication Engineers

  141. B-10-50 1 Gsymbol/s, 6-channel frequency division multiplexed 64 QAM coherent optical transmission

    Goto Hiroki, Okamoto Seiji, Omiya Tatsunori, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2009　(2)　369-369　2009/03/04

    Publisher: The Institute of Electronics, Information and Communication Engineers

  142. B-10-49 12 Gbit/s, 64 QAM-OFDM coherent optical transmission

    Omiya Tatsunori, Goto Hiroki, Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2009　(2)　368-368　2009/03/04

    Publisher: The Institute of Electronics, Information and Communication Engineers

  143. B-10-77 10 Gbit/s photonic crystal fiber transmission with a l.1μm directly-modulated VCSEL

    Koizumi Kengo, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　396-396　2009

    Publisher: The Institute of Electronics, Information and Communication Engineers

  144. B-10-67 Delivery of a Cs optical atomic clock by using JGN II optical networks

    Yoshida Masato, Kashiwamura Ikuro, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2008　(2)　210-210　2008/09/02

    Publisher: The Institute of Electronics, Information and Communication Engineers

  145. A 1.3GHz ultranarrow FBG optical filter with 20-dB side lobe suppression

    MORI Anne, KASAI Keisuke, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　108　(194)　103-108　2008/08/21

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A fiber Bragg grating (FBG) is an attractive optical filter device because of its narrow wavelength selectivity, low loss, compactness, and low cost. Therefore, it is useful for applications such as dense wavelength division multiplexing and coherent optical communication systems. These applications require both a narrow bandwidth and a high side lobe suppression ratio. We have already demonstrated a 1.3GHz ultranarrow FBG filter with a side lobe suppression ratio of 13dB. In this paper, we report a 1.3GHz FBG filter with a side lobe suppression ratio as high as 20dB by combining a uniform FBG and a λ/4 shifted FBG.

  146. B-10-97 Polarization multiplexed 1 Gsymbol/s, 128 QAM coherent optical transmission

    Goto Hiroki, Kasai Keisuke, Yoshida Masato, Nakasawa Masataka

    Proceedings of the IEICE General Conference　2008　(2)　380-380　2008/03/05

    Publisher: The Institute of Electronics, Information and Communication Engineers

  147. Polarization-multiplexed 1 Gsymbol/s,128 QAM (14 Gbit/s) coherent optical transmission over 160 km with a 1.4 GHz bandwidth

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2008　(0)　45-45　2008

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2008.0_45 　

  148. 1.3 GHz ultranarrow FBG optical filter with 20-dB side lobe suppression

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2008　(0)　46-46　2008

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2008.0_46 　

  149. C-4-5 A regeneratively mode-locked fiber laser with a repetition rate stability of 4.9×10^<-15> using a hydrogen maser PLL

    Yoshida M., Hirayama T., Nakazawa M., Hagimoto K., Ikegami T.

    Proceedings of the Society Conference of IEICE　2007　(1)　211-211　2007/08/29

    Publisher: The Institute of Electronics, Information and Communication Engineers

  150. C-4-7 Aλ/4-shifted distributed feedback semiconductor fiber ring laser with a high OSNR and a narrow linewidth

    Ho Thi Quynh Anh, Suzuki Akihito, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2007　(1)　213-213　2007/08/29

    Publisher: The Institute of Electronics, Information and Communication Engineers

  151. B-10-54 1Gsymbol/s, 64QAM coherent optical transmission with a high spectral efficiency using a Nyquist filter

    Kasai Keisuke, Hongo Jumpei, Goto Hiroki, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2007　(2)　248-248　2007/08/29

    Publisher: The Institute of Electronics, Information and Communication Engineers

  152. C-4-3 A soliton fiber laser with a single-wall carbon nanotube as a saturable absorber

    Shirato Takafumi, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka, Kaino Toshikuni, Komatsu Kyoji

    Proceedings of the Society Conference of IEICE　2007　(1)　209-209　2007/08/29

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1349-1369

  153. Application of carbon nanotubes to ultrashortpulse fiber lasers

    中沢正隆, 廣岡俊彦, 吉田真人, 戒能俊邦, 小松京嗣

    Material stage　7　(4)　37-40　2007/07

    Publisher: 技術情報協会

    ISSN： 1346-3926

  154. C-4-25 Improvement of output characteristics of an optical frequency tunable 40GHz, picosecond mode-locked fiber laser

    Yoshida Masato, Kasai Keisuke, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2007　(1)　287-287　2007/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  155. C-4-29 Frequency stability improvement of mode-locked laser-type optical atomic clock with an optically pumped Cs gas cell

    Hirayama Toru, Yoshida Masato, Nakazawa Masataka, Hagimoto Ken, Ikegami Takeshi

    Proceedings of the IEICE General Conference　2007　(1)　291-291　2007/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  156. B-10-68 Performance of optical phase-locked loop over 500 km for coherent transmission using heterodyne detection

    Kasai Keisuke, Hongo Jumpei, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2007　(2)　407-407　2007/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  157. BS-7-1 Coherent QAM transmission using a frequency-stabilized laser and an optical phase-locked-loop

    Yoshida Masato, Kasai Keisuke, Hongou Jumpei, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2007　(2)　"S-47"-"S-48"　2007/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  158. 1.5 μm 13C2H2 frequency-stabilized fiber laser and its application to QAM coherent transmission with high spectral efficiency

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2007　(0)　29-29　2007

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2007.0_29 　

  159. B-10-54 64 and 128 coherent QAM preliminary transmission experiments using a frequency-stabilized laser and a local oscillator

    Nakazawa Masataka, Hongou Jumpei, Kasai Keisuke, Yoshida Masato

    Proceedings of the Society Conference of IEICE　2006　(2)　248-248　2006/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  160. C-4-16 An optical frequency tunable 40GHz, picosecond mode-locked fiber laser

    Yoshida Masato, Kasai Keisuke, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2006　(1)　230-230　2006/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  161. C-4-17 Proposal and its operation of mode-locked laser-type optical atomic clock with an optically pumped Cs gas-cell

    Hirayama Toru, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2006　(1)　231-231　2006/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  162. 40Gbit/s (4x10Gbit/s)-3km WDM transmission using 850nm VCSEL, AWG, and PCF

    OIKAWA Yosuke, HASEGAWA Hideaki, HIROOKA Toshihiko, YOSHIDA Masato, NAKAZAWA Masataka, SUZUKI Kenya, INOUE Yasuyuki

    IEICE technical report　106　(211)　27-32　2006/08/17

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Recently, a photonic crystal fiber (PCF), which has a core region surrounded by multiple air holes, has received a lot of attention because of its new characteristics such as endlessly single-mode operation and arbitrary dispersion control. By combining a VCSEL, a Si-APD, and a PCF we can construct inexpensive and high-speed communication systems such as 10-40Gbit/s Ethernet. In this paper, we report the first 10Gbit/s x 4 channel WDM transmission over 3km at 850nm using a single-mode PCF without power penalty. We used a special arrayed waveguide grating (AWG) operating at 850nm as a multiplexer and a demultiplexer.

  163. Performance improvement of an acetylene (C_2H_2) frequency-stabilized fiber laser

    KASAI Keisuke, SUZUKI Akihito, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　106　(211)　57-62　2006/08/17

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    An erbium-doped fiber with high Er-ion concentration generally causes output power fluctuation and self-pulsing operation in an erbium fiber laser due to relaxation oscillation. In this report, we employed a new EDF with high Er- and Al-ion concentrations in order to suppress relaxation oscillation and increase output power of the laser. As a result, the output power was more than doubled and the power fluctuation halved. Furthermore the frequency stability of the ^<13>C_2H_2 frequency-stabilized erbium fiber laser reached as high as 1.3×10^<-11> for τ=1s and 2.0×10^<-11> for τ=10^2s. The short term stability of τ=1s was also improved.

  164. Linewidth broadening in high-speed optical comb transmission using a picosecond mode-locked laser

    OSAWA Kou, HIROOKA Toshihiko, YOSHIDA Masato, NAKAZAWA Masataka

    IEICE technical report　106　(211)　63-68　2006/08/17

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    An optical pulse train generated from a mode-locked laser has neatly repetitive longitudinal modes in the frequency domain. Since the interval between adjacent modes is defined by the repetition frequency of the laser and each mode has a narrow linewidth with a high SN ratio, the modes can be used for highly accurate optical frequency measurement. Recently, the delivery of such optical frequency standards through optical fiber networks has become an important subject. When we transmit longitudinal modes through an optical fiber network, it is very important to investigate the deformation in the power spectrum of the modes that occurs during the transmission. In this paper, we report the spectrum deformation of the longitudinal mode that occurs during long-haul transmission through dispersion-shifted fiber. We used a 10GHz mode-locked fiber laser with a linewidth as narrow as 1kHz as the signal source. As a result, we found that the deformation of the longitudinal mode power spectrum occurs mainly at the tail of the spectrum and the linewidth broadening increases in proportion to the transmission distance. The main reason for the linewidth broadening in the present experiment was the phase fluctuation of the optical fiber caused by temperature fluctuation or vibration.

  165. B-10-81 10Gb/s-5km transmission at 850nm using a photonic crystal fiber, VCSEL, and Si-APD

    Hasegawa Hideaki, Oikawa Yosuke, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2006　(2)　401-401　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  166. C-4-2 The fabrication and oscillation characteristics of a polarization-maintained distributed feedback fiber laser at 1.55μm

    Suzuki Akihito, Takahashi Yohei, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2006　(1)　246-246　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  167. C-4-3 A ring-cavity λ/4-shift polarization-maintaining DFB fiber laser and the improvement of the oscillation characteristics

    Takahashi Yohei, Suzuki Akihito, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2006　(1)　247-247　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  168. C-4-4 Characteristics of a ^<13>C_2H_2 frequency-stabilized, polarization-maintained fiber laser at 1.54μm : Measurement of frequency stability with beat note signal

    Kasai Keisuke, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2006　(1)　248-248　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  169. C-4-5 A 1.5μm long cavity single-frequency fiber laser using SOA

    Ono Atsushi, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2006　(1)　249-249　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  170. C-14-7 Ultrastable Cs optical atomic clock with digital frequency stabilization using rectangular modulation

    Hirayama T., Yoshida M., Nakazawa M., Hagimoto K., Koga Y., Ikegami T.

    Proceedings of the IEICE General Conference　2006　(1)　274-274　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  171. C-4-7 Polymer saturable absorber materials in 1.5μm band using PMMA and PS with single-wall carbon nanotubes and their application to a femtosecond laser

    Nakazawa Masataka, Nakahara Seiji, Hirooka Toshihiko, Yoshida Masato, Kaino Toshikuni, Komatsu Kyoji

    Proceedings of the IEICE General Conference　2006　(1)　251-251　2006/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 1349-1369

  172. 10 Gb/s x 4 channel WDM transmission over a 3 km-long photonic crystal fiber in the 800 nm region

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2006　(0)　13-13　2006

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2006.0_13 　

  173. Fiber transmission of microwave and optical standard signals using a mode-locked fiber laser in the GHz region

    Tohoku-Section Joint Convention Record of Institutes of Electrical and Information Engineers, Japan　2006　(0)　14-14　2006

    Publisher: Organizing Committee of Tohoku-Section Joint Convention of Institutes of Electrical and Information Engineers, Japan

    DOI： 10.11528/tsjc.2006.0_14 　

  174. C-3-107 Fabrication of a zero-dispersion, dispersion-flattened photonic crystal fiber in the 800 nm region

    Hasegawa Hideaki, Oikawa Yosuke, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2005　(1)　251-251　2005/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  175. C-4-13 A C_2H_2 frequency-stabilized fiber laser with a LiNbO_3 optical frequency modulator and a PLL circuit

    Kasai Keisuke, Yoshida Masato, Nakazawa Masataka, Shiota Kazunori, Masuda Shin

    Proceedings of the Society Conference of IEICE　2005　(1)　294-294　2005/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  176. C-3-76 Broadband dispersion measurement of a photonic crystal fiber with pico-second streak camera and SC light

    Hasegawa Hideaki, Oikawa Yousuke, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2005　(1)　246-246　2005/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  177. C-4-25 An ultrastable PLL mode-locked fiber laser with hydrogen maser clock

    Yoshida M., Hirayama T., Yakabe M., Nakazawa M., Koga Y., Hagimoto K., Ikegami T.

    Proceedings of the IEICE General Conference　2005　(1)　332-332　2005/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  178. C-4-28 Construction of a ^<13>C_2H_2 (acetylene) frequency-stabilized, single-polarization fiber ring laser

    Kasai Keisuke, Yoshida Masato, Nakazawa Masataka, Shiota Kazunori, Masuda Shin

    Proceedings of the IEICE General Conference　2005　(1)　335-335　2005/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  179. 平成15年度学術奨励賞受賞記(I)(NEWS LETTER)

    吉田 真人

    電子情報通信学会論文誌. C, エレクトロニクス　87　(9)　C2-C3　2004/09/01

    Publisher: 一般社団法人電子情報通信学会

    ISSN： 1345-2827

  180. Measurement of frequency stability of a Cs optical atomic clock using an opto-microwave oscillator

    YAKABE Masatsugu, NITO Ko, YOSHIDA Masato, NAKAZAWA Masataka, KOGA Yasuki, HAGIMOTO Ken, IKEGAMI Takeshi

    Technical report of IEICE. OFT　104　(262)　19-24　2004/08/20

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We demonstrate an ultrastable cesium (Cs) atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser. By adopting an optically pumped Cs beam tube that has a 1 m-long interaction cavity with a linewidth of 110 Hz, the frequency stabilities are reached as high as 4.8×10^<-12> for τ=1s and 6.3×10^<-13> for τ=50s.

  181. Oscillation characteristics of a 10GHz harmonically and regeneratively mode-locked SOA fiber laser

    ONO Atsushi, YOSHIDA Masato, NAKAZAWA Masataka

    Technical report of IEICE. OFT　104　(262)　25-30　2004/08/20

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A harmonically and regeneratively mode-locked erbium-doped fiber laser can easily produce picosecond transform-limited pulses in the GHz region, so it is very attractive as a light source for an ultrafast optical communication. This fiber laser has a long cavity length and a high O-value of cavity, thus a narrow linewidth (less than 1kHz) of the longitudinal mode can be obtained. This laser is also utilized as a high pure microwave oscillator by using the longitudinal self-beat signal. In this report, we described a 10GHz mode-locked fiber laser using a semiconductor optical amplifier (SOA) instead of a conventional erbium-doped fiber (EDF) as a gain medium, which has a wide tunable range of the cavity length. We measured the linewidth of the laser as a function of the laser cavity.

  182. Development of a C_2H_2 (acetylene) frequency-stabilized and single-polarization fiber laser

    KASAI Keisuke, YOSHIDA Masato, NAKAZAWA Masataka

    Technical report of IEICE. OFT　104　(262)　31-36　2004/08/20

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A frequency-stabilized fiber ring laser using linear absorption line of acetylene molecules is described. The output beam has no frequency modulation. A Fiber Brrag Grating (FBG) with a 3.7GHz bandwidth enabled single-frequency operation by selecting only one longitudinal-mode. The laser frequency was continuously tuned over 2GHz with a longitudinal-mode tracking technique using FBG and was locked to C_2H_2 molecules. The frequency stability (Allan variance) estimated from error signals reached as high as 1.7×10^<-10> for τ=1s and 1.7×10^<-11> for τ=1×10^2s.

  183. C-3-26 Optical filter characteristics of an ultra-narrow band polarization-maintaining fiber Bragg grating and its application to laser frequency tuning

    Yoshida Masato, Kasai Keisuke, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2004　(1)　199-199　2004/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  184. C-3-144 Splicing characteristics between a photonic crystal fiber and a conventional fiber

    Kikegawa Manabu, Hasegawa Hideaki, Yoshida Masato, Hirooka Toshihiko, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2004　(1)　318-318　2004/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  185. C-4-1 Stimulated Brillouin Scattering in DDF soliton compression of an ultrahigh-speed optical pulse train

    Ono Shimpei, Hirooka Toshihiko, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2004　(1)　329-329　2004/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  186. C-4-19 Oscillation characteristics of a 40 GHz regeneratively mode-locked erbium-doped fiber laser

    Harada Shinji, Yoshida Masato, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2004　(1)　347-347　2004/03/08

    Publisher: The Institute of Electronics, Information and Communication Engineers

  187. Measurements of longitudinal mode linewidth and relative intensity noise in ultrahigh-speed mode-locked semiconductor lasers

    HANEDA Kentaro, YOSHIDA Masato, YOKOYAMA Hiroyuki, OGAWA Yo, NAKAZAWA Masataka

    Technical report of IEICE. OPE　103　(523)　49-52　2003/12/11

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Recently, mode-locked laser diodes (MLLD's) have been intensively studied as light sources for ultrahigh-speed optical communication systems. To improve the timing-jitter and the frequency and amplitude stability of a high repetition rate pulse source, it is important to investigate the longitudinal mode linewidth and relative intensity noise. However, there has been no report on such measurements to date. In this paper we measure the longitudinal mode linewidth and relative intensity noise of 10 GHz and 40 GHz MLLDs and describe new results on these characteristics.

  188. FDTD Analysis of Fresnel Reflection at a Splice between a Photonic Crystal Fiber and a Conventional Fiber

    Hirooka Toshihiko, Hori Yusuke, Hasegawa Hideaki, Yoshida Masato, Nakazawa Masataka

    Proceedings of the Society Conference of IEICE　2003　(1)　214-214　2003/09/10

    Publisher: The Institute of Electronics, Information and Communication Engineers

  189. C-4-24 モード同期半導体レーザの縦モード線幅およびその強度雑音の測定

    羽根田 健太郎, 吉田 真人, 横山 弘之, 小川 洋, 中沢 正隆

    電子情報通信学会ソサイエティ大会講演論文集　2003　(1)　300-300　2003/09/10

    Publisher: 一般社団法人電子情報通信学会

  190. Observation of an optimum air-hole tapering for splicing between a conventional fiber and a photonic crystal fiber and the reduction of Fresnel reflection

    KIKEGAWA Manabu, HASEGAWA Hideaki, YOSHIDA Masato, HIROOKA Toshihiko, NAKAZAWA Masataka

    Technical report of IEICE. OFT　103　(257)　51-56　2003/08/14

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    We have already reported about an observation of a huge Fresnel reflection at a splicing point between a photonic crystal fiber (PCF) and a conventional fiber. This was caused by the difference of the refractive index in the claddings, which leads to a serious problem when utilizing PCF in optical communications. In this paper, the splicing characteristics between a PCF and a conventional fiber were measured in detail, and a splicing condition for suppressing the Fresnel reflection to below the Rayleigh scattering level was clarified. We also measured the cross-sectional structures of PCF near the splicing point by SEM, and a relation between reduction of the Fresnel reflection and air-hole form in the cladding of PCF was discussed.

  191. Observation of Ramsey fringe of a Cs resonance with an ultra-stable pure microwave generated by a regeneratively mode-locked fiber laser

    YAKABE Masatsugu, NITO Ko, YOSHIDA Masato, NAKAZAWA Masataka

    Technical report of IEICE. OFT　103　(257)　89-94　2003/08/14

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A regeneratively mode-locked fiber laser can self-oscillate stably without a synthesizer. The laser has jitter less than 100 fs, so that a beat signal obtained between the longitudinal laser modes can be used as an ultra-stable pure microwave signal. By using this laser as an optical microwave oscillator, a new type of Cs optical atomic clock can be composed and have already been confirmed the operation. In this paper, we observed an atomic resonance of Cs (Ramsey fringe) at 9.1926 GHz for the first time with the optical microwave oscillator, and measured the fundamental characteristics of the Cs optical atomic resonance.

  192. Observation of huge Fresnel reflections at splicing points between a photonic crystal fiber and a conventional fiber and their suppression method

    Yoshida Masato, Kikegawa Manabu, Nakazawa Masataka

    Proceedings of the IEICE General Conference　2003　(1)　229-229　2003/03/03

    Publisher: The Institute of Electronics, Information and Communication Engineers

  193. Observation of huge Fresnel reflection at a splicing point between a photonic crystal fiber and a conventional fiber and its suppression

    YOSHIDA Masato, NISHIMURA Naoya, NAKAZAWA Masataka

    Technical report of IEICE. PS　102　(267)　1-6　2002/08/15

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    It is possible to realize index-guiding optical fibers by forming small air holes in the fiber cladding instead of doping its core with high-index materials. These fibers are called index-guiding type photonic crystal fibers. The fibers have very interesting new features including endlessly single-mode operation, zero GVD in the visible region, and easy control of the spot-size because of the strongly guiding characteristics that result from the very high relative refractive index between the core and cladding with air holes. In this study, we describe splicing characteristics between photonic crystal fibers and conventional fibers. A large Fresnel reflection is observed at the splicing point, which causes serious problems when utilizing photonic crystal fibers in conventional optical communications. A reduction method of the Fresnel reflection is also presented.

  194. Longitudinal linewidth measurements of 10GHz, picosecond modelocked erbium-doped fiber lasers using a heterodyne detection method

    CHOI Samuel, YOSHIDA Masato, NAKAZAWA Masataka

    Technical report of IEICE. PS　102　(267)　45-50　2002/08/15

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    Harmonically mode-locked erbium-doped fiber lasers, which operate in the 10〜40 gigahertz region, have attracted widespread attention in the field of optical communication as light sources for ultra high-speed optical communication, because of their high-quality output pulses. However, the amount of longitudinal linewidth in these lasers has not yet been made clear. In this study, we measure the linewidth of a regeneratively and harmonically mode-locked erbium-doped fiber ring laser (ML Fiber Laser) for the first time by using a heterodyne method, and we show that the linewidth is less than 250 Hz.

  195. B-13-1 Polarization Mode Dispersion Characteristics Analysis of Optical Fiber based on Delayed Self-Heterodyne OFDR Technique

    Zou Nianyu, Yoshida Masato, Nakamura Koichiro, Ito Hiromasa

    Proceedings of the Society Conference of IEICE　2001　(2)　486-486　2001/08/29

    Publisher: The Institute of Electronics, Information and Communication Engineers

  196. A frequency-shifted feedback fiber laser and its application to optical measurements

    YOSHIDA M., NAKAZAWA M., ITO H.

    IEICE technical report. Component parts and materials　101　(258)　53-58　2001/08/17

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    In frequency-shifted feedback lasers (FSF lasers), a frequency shift is imposed on an intracavity light field by feedback of the first-order diffracted light of an acousto-optic modulator. In this report, we describe the performance of the FSF laser with an erbium-doped fiber as a gain medium and its application to measurements for group velocity dispersion and polarization mode dispersion of optical fibers. We also describe a new FSF laser which incorporates an active mode-locking technique. Because of the mode-locking mechanism, the phase between the modes are completely locked, and this indicates that one can greatly improve the signal to noise ratio of the beat signal (> 20 dB)in optical homodyne measurements.

  197. Optical frequency domain reflectometry domain with a frequency-shifted feedback mode locked erbium doped fiber laser

    Yoshida M., Fujimoto M., Nakamura K., Nakazawa M., Ito H.

    Proceedings of the Society Conference of IEICE　2000　(2)　432-432　2000/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  198. Measurement of group velocity dispersion of optical fiber with a frequency-shifted feedback laser

    Yoshida M., Miyamoto T., Nakamura K., Ito H.

    Proceedings of the IEICE General Conference　2000　(1)　328-328　2000/03/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  199. A new technique for measuring dispersion of optical fibers with a frequency-shifted feedback fiber laser : group velocity dispersion measurement

    YOSHIDA M., MIYAMOTO T., NAKAMURA K., ITO H.

    Technical report of IEICE. OFT　99　(650)　67-72　2000/02/23

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A new technique is presented for measuring the group velocity dispersion(GVD)of optical fibers with optical frequency domain reflectometry technique. In this method, a change of frequency chirp rate of a light source caused by the effect of GVD is measured. Using the frequency-shifted feedback laser as a light source, a high performance of measuring of GVD and a simplification of the system were demonstrated.

  200. A new technique for measuring dispersion of optical fibers with a frequency-shifted feedback fiber laser : polarization mode dispersion measurement

    MIYAMOTO T., YOSHIDA M., NAKAMURA K., ITO H.

    Technical report of IEICE. OFT　99　(650)　73-78　2000/02/23

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

    More details Close

    A new technique is presented for measuring polarization mode dispersion(PMD)of the opcital fiber with the optical frequency domain reflectmetry(OFDR)technicue. Using the frequency-shifted feedback(FSF)laser as a light source, a high performance of measuring of PMD and a simplification of system were demonstrated

  201. Measurement of the Group Velocity Dispersion of Optical Fibers by Using a Frequency-Shifted-Feedback Optical Fiber Laser

    Iiyama K., Maeda T., Takamiya S., Yoshida M., Nakamura K., Ito H.

    Proceedings of the IEICE General Conference　621-621　2000

    Publisher: The Institute of Electronics, Information and Communication Engineers

  202. Long distance measurement of 150km with a frequency-shifted feedback fiber laser

    Yoshida M., Miyamoto T., Nakamura K., Ito H.

    Proceedings of the Society Conference of IEICE　1999　(1)　172-172　1999/08/16

    Publisher: The Institute of Electronics, Information and Communication Engineers

  203. 会議報告 CLEO/QELS'99

    中村 孝一郎, 吉田 真人, 浦田 佳治

    O plus E　21　(7)　793-795　1999/07

    Publisher: 新技術コミュニケ-ションズ

    ISSN： 0911-5943

  204. Measurement of group velocity dispersion of optical fiber with a frequency-shifted feedback laser

    YOSHIDA M., MIYAMOTO T., HARA T., NAKAMURA K., ITO H.

    Technical report of IEICE. OPE　98　(586)　19-24　1999/02/10

    Publisher: The Institute of Electronics, Information and Communication Engineers

    More details Close

    A new technique is presented for measuring the group velocity dispersion (GVD) of optical fibers with optical frequency domain reflectometry (OFDR) technique. Using the frequency-shifted feedback (FSF) laser as a light source, a high performance of measuring of GVD and a simplification of the system were demonstrated.

  205. The automatic measurement System of group velocity dispersion using a frequency-shifted feedback laser

    Miyamoto T., Yoshida M., Hara T., Nakamura K., Ito H.

    Proceedings of the IEICE General Conference　225-225　1999

    Publisher: The Institute of Electronics, Information and Communication Engineers

  206. Long Distance Optical Reflectometry by a FSF Laser

    Nakamura Koichiro, Hara Takefumi, Yoshida Masato, Ito Hiromasa

    Proceedings of the Society Conference of IEICE　1998　(1)　195-195　1998/09/07

    Publisher: The Institute of Electronics, Information and Communication Engineers

  207. Characteristics of a Frequency-Shifted Feedback Fiber Laser

    YOSHIDA M., NAKAMURA K., MIYAHARA T., ITO H.

    Technical report of IEICE. LQE　98　(41)　19-24　1998/05/11

    Publisher: The Institute of Electronics, Information and Communication Engineers

    More details Close

    In the frequency-shifted feedback laser (FSF laser), a frequency shift is imposed on an intracavity light field by feedback of the first order diffracted light of an acousto-optic modulator (AOM). Here we report the first observation of a chirped frequency comb output from this type of laser with erbium-doped fiber as a gain medium, and investigate its application to optical reflectometry. The spatial resolution is demonstrated to be 1.5 mm.

  208. Measuring limits of long distance and high resolution OFDR using FSF-Laser

    Miyahara T., Nakamura K., Yoshida M., Hara T., Ito H.

    Proceedings of the IEICE General Conference　1998　(1)　369-369　1998/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

  209. Oscillating characteristic of FSF Fiber Laser and its application to reflectometry

    Yoshida M., Nakamura K., Miyahara T., Ito H.

    Proceedings of the IEICE General Conference　1998　(1)　370-370　1998/03/06

    Publisher: The Institute of Electronics, Information and Communication Engineers

Show all ︎Show first 5

Industrial Property Rights 16

  1. 周波数シフト帰還型モード同期レーザ及び周波数シフト帰還型再生モード同期レーザの研究(特許)

    中沢 正隆, 伊藤 弘昌, 吉田 真人

    Property Type: Patent

  2. 周波数シフト帰還型モード同期レーザ及び周波数シフト帰還型再生モード同期レーザ

    中沢正隆, 伊藤弘昌, 吉田真人

    Property Type: Patent

  3. 偏波モード分散測定装置および偏波モード分散測定方法に関する研究(特許)

    伊藤 弘昌, 吉田 真人, 宮本 敏行, 中村 孝一郎

    Property Type: Patent

  4. 群速度分散測定装置および群速度分散測定方法に関する研究(特許)

    Property Type: Patent

  5. 空間多重光伝送システム

    吉田真人, 中沢正隆

    Property Type: Patent

  6. パルス光源及びそれを用いたシステム

    中沢正隆, 廣岡俊彦, 吉田真人

    Property Type: Patent

  7. 光注入同期型局発光源、及び光伝送方法

    中沢正隆, 吉田真人, 葛西恵介

    Property Type: Patent

  8. エルミートガウスパルス光源

    中沢正隆, 廣岡俊彦, 吉田真人

    Property Type: Patent

  9. 光伝送方法および光伝送装置

    中沢正隆, 廣岡俊彦, 吉田真人, 葛西恵介

    Property Type: Patent

  10. 局発光発生装置、受信装置及び局発光生成方法

    中沢正隆, 廣岡俊彦, 吉田真人, 葛西恵介

    Property Type: Patent

  11. 局発光発生装置、受信装置及び局発光発生方法

    中沢正隆, 廣岡俊彦, 吉田真人, 葛西恵介

    Property Type: Patent

  12. 光ファンクションジェネレータ

    中沢正隆, 廣岡俊彦, 吉田真人

    Property Type: Patent

  13. 光ファンクションジェネレータ

    中沢正隆, 廣岡俊彦, 吉田真人

    Property Type: Patent

  14. 光中継装置及び光中継方法

    中沢正隆, 廣岡俊彦, 吉田真人, 葛西恵介

    Property Type: Patent

  15. 光秘匿通信システムおよび光秘匿通信装置

    中沢正隆, 吉田真人, 廣岡俊彦

    Property Type: Patent

  16. デジタルコヒーレント伝送システム

    中沢正隆, 吉田真人, 葛西恵介, 廣岡俊彦

    Property Type: Patent

Show all Show first 5

Research Projects 14

  1. High-capacity complex reservoir computing based on ultrahigh-speed coherent optical pulse transmission technology

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2024/04/01 - 2028/03/31

  2. 量子インターネット実現に向けた要素技術の研究開発

    代表者, 中沢正隆, 分担者, 吉田真人, 廣岡俊彦, 葛西恵介

    Offer Organization: 総務省

    System: ICT重点技術の研究開発プロジェクト

    Institution: 国立大学法人東北大学

    2023/07 - 2028/03

  3. 先進的サイバー防御機能・分析能力強化 セキュアな量子情報通信技術の開発

    代表者, 吉田真人, 分担者, 中沢正隆, 廣岡俊彦, 葛西恵介

    Offer Organization: 経済産業省

    System: 経済安全保障重要技術育成プログラム（再委託）

    Institution: 国立大学法人東北大学

    2024/09 - 2026/03

  4. Development of multi-scale observation techniques for monitoring slow-to-fast earthquakes

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Transformative Research Areas (A)

    Institution: The University of Tokyo

    2021/09 - 2026/03

  5. 振幅・位相および時間情報を用いた３次元光秘匿通信技術の研究開発

    吉田 真人

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 基盤研究(A)

    Category: 基盤研究(A)

    Institution: 東北大学

    2021/04 - 2025/03

    More details Close

    初年度は、これまでに開発してきた光の位相と振幅を用いた2次元物理暗号へ、新たに時間軸におけるデータの拡散動作を導入した3次元光秘匿通信の動作原理を実証した。具体的には、送信機として任意波形生成装置を使用し、受信器としてデジタルオシロスコープを用いた単一チャネルのオフライン伝送実験の結果をもとに、時間軸のデータ拡散動作を追加することによる安全性の向上効果を検証した。その結果、8ビット以上の乱数を用いた時間拡散を利用することにより、盗聴者が1シンボル分の正しい情報を得るために必要な信号の受信回数を1桁以上高められることを明らかにした。これは暗号化に用いる信号の多値度を4倍（2ビット）高めることに相当する。言い換えると、一定の安全性を確保することを考えた場合に、時間領域の拡散効果を利用することにより暗号化信号の多値度を2ビットだけ下げることができ、より汎用性の高い電子部品（D/A、A/D変換器）を送受信装置に利用することが可能となる。このように提案する光秘匿通信方式の実用性を高められることを明らかにした。 また本年度は、上述したオフライン伝送実験の成果をもとに、リアルタイム動作を実現するためのFPGA（Field Programmable Gate Array）回路の作製に着手した。具体的には8ビットの乱数列生成器を追加し、それを用いて申請書で提案した2種類の時間拡散動作（方式１：ダミー信号を利用する方式、方式２：ダミー信号は用いず、暗号化データの順序を時間軸上で入れ替える）を実現するためのFPGA回路を設計した。

  6. 新たな社会インフラを担う革新的光ネットワーク技術の研究開発 課題Ⅱ

    吉田真人

    Offer Organization: 総務省

    System: 情報通信技術の研究開発

    Institution: 東北大学

    2018/04 - 2022/03

  7. 多機能なコヒーレントナイキストパルスの提案とそれを用いた超高速・高効率光伝送技術

    中沢 正隆, 廣岡 俊彦, 吉田 真人, 葛西 恵介

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別推進研究

    Category: 特別推進研究

    Institution: 東北大学

    2014 - 2018

    More details Close

    本年度はナイキストパルス伝送における高速化ならびに周波数利用効率拡大への取り組みとして、(a)ピコ秒パルス光源の光位相同期技術の開発とそれを用いた単一チャネル7.68 Tbit/s, 周波数利用効率9.7 bit/s/Hzの超高速・高効率コヒーレントナイキストパルス伝送、および(b)ノンコヒーレントナイキストパルス伝送を用いた単一チャネル10 Tbit/s伝送、の2つを中心に取り組んだ。 (a)に関しては、コヒーレントナイキストパルスを用いて単一チャネル3.84 Tbit/sの超高速伝送を10 bit/s/Hzを上回る高い周波数利用効率で実現した。具体的には、送信用光源だけでなく新たに受信用のLO光源としてもモード同期ファイバレーザ(MLFL)を用いることでナイキストパルスの高OSNR化を図った。さらに、送受信用MLFL間の光位相同期回路を新たに開発した。これらの要素技術により、9.7 bit/s/Hzの極めて周波数利用効率を有する単一チャンネル7.68 Tbit/s-150km超高速コヒーレントナイキストパルス伝送に初めて成功した。10 Tbit/s近い伝送速度で10 bit/s/Hzに迫る高い周波数利用効率を実現した前例はなく、これらの結果はナイキストパルスが極めて優れた伝送性能を有するパルスであることを示している。 一方(b)に関しては、ノンコヒーレントナイキストパルスのシンボルレートを1.28 Tsymbol/sから2.56 Tsymbol/sへ高速化することにより、単一チャネルで10.2 Tbit/sの超高速伝送を世界で初めて実現した。具体的には、超短ナイキストパルス(パルス幅 : 340 fs)の生成、ファイバ伝送路の4次分散まで考慮した高次分散の高精度な補償、信号光と制御光の間のドリフトを抑制した超高速光多重分離回路(ゲート幅 : 230 fs)、RZ-CW変換法による受信信号のS/N比の向上、等の開発に取り組んだ。その結果、単一チャネル10.2 Tbit/s信号の300km伝送に世界で初めて成功した。このときの周波数利用効率は2.5 bit/s/Hzであった。本実験ではデジタルコヒーレント伝送に見られるオフライン処理ではなく誤り率をオンラインで測定しており、超高速伝送を簡便な構成で実現できる方式として有用である。

  8. セキュアフォトニックネットワーク技術の研究開発

    吉田真人

    Offer Organization: NICT

    System: 高度通信・放送研究開発委託研究

    Institution: 東北大学

    2011/04 - 2016/03

  9. Development of hybrid mode-locked laser with CNT saturable absorber and optical modulator

    YOSHIDA Masato

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2012/04 - 2014/03

    More details Close

    We developed a hybrid mode-locked laser with a saturable absorber and an optical modulator to generate a femtosecond pulse with a GHz repetition rate. We studied carbon nanotube, graphene, and semiconductor devices as a saturable absorber. Then we inserted these devices into an active mode- locked laser, in which the dispersion and the nonlinearity were optimized for soliton pulse generation. As a result, we have successfully generated a 500 fs pulse with a 10 GHz repetition rate.

  10. GHz mode-locked pulse laser with simultaneously stabilized optical frequency and repetition rate and its applications

    NAKAZAWA MASATAKA, YOSHIDA Masato

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)

    Category: Grant-in-Aid for Scientific Research (S)

    Institution: Tohoku University

    2009/05 - 2014/03

    More details Close

    We have demonstrated for the first time a mode-locked pulse laser with simultaneo-usly stabilized optical frequency and repetition rate by using a Cs atomic resonance and an acetylene mol-ecular absorption line, respectively. We also successfully demonstrated a 440 fs short pulse generation byemploying a saturable absorber in the laser cavity for narrowing the pulse width. Furthermore,we applied apulse source based on a frequency stabilized CW laser to coherent optical pulse transmission, and we have successfully demonstrated for the first time a 1.92 Tbit/s single channel transmission with 64 QAM signal.

  11. 革新的光ファイバ技術に関する研究開発

    吉田真人

    Offer Organization: NICT

    System: 高度通信・放送研究開発委託研究

    Institution: 東北大学

    2010/04 - 2013/03

  12. Research on optical pulse source and ultra-high speed optical transmission technologies with 1. 1μm VCSEL

    YOSHIDA Masato

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2009 - 2011

    More details Close

    This work aims to develop light source and ultra-high speed optical transmission technologies in the 1. 1μm band. First, we demonstrated a 10 Gbit/s transmission over 5 km with a 1. 1μm directly modulated single-mode VCSEL. Next, we developed a 10 GHz, 1. 1ps regeneratively mode-locked Yb fiber laser and optical time division multiplexing and demultiplexing circuits. Then, with these devices, we demonstrated the first 160 Gbit/s ultra-high speed optical transmission system in the 1. 1μm band.

  13. Establishment of novel ultrahigh-speed distortion-free optical transmission technology using time-domain optical Fourier transformation

    NAKAZAWA Masataka, HIROOKA Toshihiko, YOSHIDA Masato

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Specially Promoted Research

    Category: Grant-in-Aid for Specially Promoted Research

    Institution: Tohoku University

    2004 - 2008

  14. 超高速光通信用高繰り返し低雑音フェムト秒パルス列の発生技術

    吉田 真人

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 若手研究(B)

    Category: 若手研究(B)

    Institution: 東北大学

    2004 - 2005

    More details Close

    本研究では次世代の大容量・超高速フォトニックネットワークを構築する上で重要な高繰り返し超短パルス光源の開発に取り組んでいる。平成16年度は40GHzの高繰り返し高調波再生モード同期ファイバレーザを開発し、パルス幅が1.5〜2.0psの高安定なパルス列を得ることに成功した。今年度はこのピコ秒パルスの圧縮技術を開発し、高繰り返しフェムト秒パルス列の生成に取り組んだ。さらに高安定フェムト秒パルス発生のために繰り返し周波数をCs共鳴線に安定化する技術に取り組んだ。 本研究では、ファイバの分散値を長手方向に対して減少させた分散減少ファイバ(DDF: Dispersion Decreasing Fiber)を用いたソリトンパルス圧縮技術を用いた。DDF中においてソリトンパルスを形成するためにはDDFへ入射する光パルス強度を数100mWまで増幅する必要がある。その際、ソリトン効果以外の非線形光学効果の影響が無視できなくなる。本研究では、繰り返し周波数が40GHzであるモード同期ファイバレーザからの出力パルスの圧縮実験を行い、 SBS (SBS: Stimulated Brillouin Scattering)の影響によりその圧縮過程が不安定になることを見出した。そこでDDFへ入射する光パルス信号に周波数変調を与えその縦モード線幅を数10MHzに拡大することによりSBSを抑制し、繰り返しが40GHzで100fsのパルス列を安定に生成することに成功した。またCsのラムゼイ共鳴線に10GHzモード同期ファイバレーザを安定化し、パルスの繰り返し周波数を10^<-11>〜10^<-12>と高安定に制御することに成功した。

Show all Show first 5

Teaching Experience 3

  1. 電気回路学I演習　東北大学工学部電気情報系

  2. 創造工学研修　東北大学工学部

  3. 学生実験A　東北大学工学部電気情報系

Other 3

  1. 光で時を刻む新Cs原子“光時計”の開発

    More details Close

    本プロジェクトは、高安定ピコ秒パルスレーザ（光マイクロ波発振器）を利用した新たなCs光原子発振器“光時計”を世界に先駆けて実現したものである。人類が持ち得る最も安定な光の時計を作製することは超高速なグローバル光ネットワークを構築する観点、特に伝送用クロックの高精度化の点において大変重要である。本プロジェクトでは世界に先駆けて新たなCs光原子時計を実現し、そのクロック信号の光ネットワークを介した遠隔配信技術を確立することを目的とした。なお、本プロジェクトは産学官連携により推進され、東北大学、産業総合技術研究所および横河電機との共同で研究開発を行った。 平成18年度までにラックマウントサイズのCs光原子発振器を試作し、平均時間1秒で1.2×10-12、100秒で8.8×10-14の高い周波数安定度を実現した。そして平成19年度は、既設のつくば―大手町間往復200 kmのJGNⅡ光ファイバ伝送路および実験室内に配置した225 km、525 kmの光ファイバ伝送路を用いて、試作したCs光原子発振器の出力光パルス信号（クロック信号）の配信実験を行ない、光ファイバ伝送に伴う高精度クロック信号のS/N、ジッタ、および周波数安定度の変化について詳細に測定した。その結果、光ファイバ伝送路の偏波モード分散の影響によりクロック信号のジッタ特性および周波数安定度の劣化が顕著に現れることを明らかにした。 マイクロ波信号の遠隔配信技術を実用化する上で、光ファイバ伝送に伴う配信した信号の品質劣化を抑制することが大変重要である。本研究成果は、その品質劣化の対策に関する新たな知見を得たものであり、本配信技術の実用性の向上に大きく貢献できる。

  2. 仙台サイバーフォレスト構想―次世代フォトニクスに関する研究

    More details Close

    本プロジェクトは、将来の超大容量光通信、高精度分光計測、光周波数標準などの実現を目指して、光周波数が超高精度に安定化できる周波数安定化レーザの研究開発に取り組んだものである。このプロジェクトは産学連携により推進され、東北大学とアドバンテスト研究所との共同で研究開発を行なってきた。その結果、世界で初めて実用レベルでの周波数安定化ファイバレーザの開発に成功した。また、本レーザの応用として、光の振幅と位相情報を同時に利用した光多値伝送システムを開発し、周波数利用効率の高いコヒーレント光QAM伝送を世界で初めて実現した。さらに、本レーザを周波数基準光源として利用したヘテロダイン型高精度光周波数計のプロトタイプを実現した。

  3. e-trace 計量器校正情報システムの研究開発

    More details Close

    モード同期ファイバレーザからの狭線幅光コム出力信号を用いて、従来の電気回路では発生することが困難であるマイクロ波～ミリ波信号を超高精度に発生することが可能である。また、この高周波信号を光ファイバネットワークを介して遠隔供給することができる。本技術は、超高精度なマイクロ波～ミリ波信号を利用し易い環境を創り出すものであり、未開拓な高周波領域における新たな測定器や応用分野の発展につながるものである。 本研究では繰り返し周波数の安定度が1×10-11以下、発振線幅が500 Hz以下である10 GHzモード同期ファイバレーザを実現した。また、150 kmの分散シフトファイバおよび分散マネジメントファイバを用いて本レーザからの光コム出力信号の長距離伝送実験を実施し、光コム間で発生するマイクロ波信号をそのS/N（> 80 dB）を劣化させることなく伝送することに成功した。