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Real-time MIMO Adaptive Equalization with Carrier-phase Recovery for Mode-division Multiplexed Optical Coherent System
K. Igarashi
Conference on Optical Fiber Communication (OFC 2023) Vol. Th1F.1 2023/03 Research paper (international conference proceedings)
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Few-Mode Fiber Technology, Deployments, and Systems
Pierre Sillard, Kaoutar Benyahya, Daiki Soma, Guillaume Labroille, Pu Jian, Koji Igarashi, Roland Ryf, Nicolas K. Fontaine, Georg Rademacher, Kohki Shibahara
Proceedings of the IEEE Vol. 110 No. 11 p. 1804-1820 2022/11 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
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Long-Haul Coupled 4-Core Fiber Transmission over 7,200 Km with Real-Time MIMO DSP
Shohei Beppu, Masahiro Kikuta, Koji Igarashi, Hiroshi Mukai, Masahiro Shigihara, Yasuo Saito, Daiki Soma, Hidenori Takahashi, Noboru Yoshikane, Takehiro Tsuritani, Itsuro Morita, Masatoshi Suzuki
IEEE Journal of Lightwave Technology Vol. 40 No. 6 p. 1640-1649 2022/03/15 Research paper (scientific journal)
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Measuring complex field waveforms of quadrature amplitude modulation optical signals using a spectrally slicing-and-synthesizing coherent optical spectrum analyzer
Koji Igarashi, Y. Kawabata, N. Urakawa
Optics Express Vol. 28 No. 15 p. 21560-570 2020/07 Research paper (scientific journal)
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Weakly coupled 10-mode-division multiplexed transmission over 48-km few-mode fibers with real-time coherent MIMO receivers
S. Beppu, Koji Igarashi, M. Kikuta, D. Soma, T. Nagai, Y. Saito, H. Takahashi, T. Tsuritani, I. Morita, M. Suzuki
Optics Express Vol. 28 No. 13 p. 19655-668 2020/06 Research paper (scientific journal)
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257-Tbit/s Weakly Coupled 10-Mode C + L-Band WDM Transmission
Daiki Soma, Shohei Beppu, Yuta Wakayama, Koji Igarashi, Takehiro Tsuritani, Itsuro Morita, Masatoshi Suzuki
IEEE Journal of Lightwave Technology Vol. 36 No. 6 p. 1375-1381 2018/03/15 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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10.16-Peta-B/s Dense SDM/WDM Transmission Over 6-Mode 19-Core Fiber Across the C plus L Band
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 Vol. 36 No. 6 p. 1362-1368 2018/03 Research paper (scientific journal)
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10.16 Peta-bit/s Dense SDM/WDM transmission over Low-DMD 6-Mode 19-Core Fibre Across C+L Band
Daiki Soma, Yuta Wakayama, Shohei Beppu, Seiya Sumita, Takehiro Tsuritani, Tetsuya Hayashi, Takuji Nagashima, Masato Suzuki, Hidenori Takahashi, Koji Igarashi, Itsuro Morita, Masatoshi Suzuki
43rd European Conference on Optical Communication (ECOC2017) Vol. ThPDP.A.1 2017/09 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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A coherent Ising machine for 2000-node optimization problems
T. Inagaki, Y. Haribara, Koji Igarashi, T. Sonobe, S. Tamate, T. Honjo, A. Marandi, P. L. McMahon, T. Umeki, K. Enbutsu, O. Tadanaga, H. Takenouchi, K. Aihara, K. Kawarabayashi, Kyo Inoue, S. Utsunomiya, H. Takesue
Science Vol. 354 No. 6312 p. 603-606 2016/12 Research paper (scientific journal)
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Ultra-dense spatial-division-multiplexed optical fiber transmission over 6-mode 19-core fibers
Koji Igarashi, Daiki Soma, Yuta Wakayama, Koki Takeshima, Yu Kawaguchi, Noboru Yoshikane, Takehiro Tsuritani, Itsuro Morita, Masatoshi Suzuki
Optics Express Vol. 24 No. 10 p. 10213-10231 2016/05/16 Research paper (scientific journal)
Publisher: OSA - The Optical Society
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2.05 Peta-bit/s super-nyquist-WDM SDM transmission using 9.8-km 6-mode 19-core fiber in full C band
D. Soma, K. Igarashi, Y. Wakayama, K. Takeshima, Y. Kawaguchi, N. Yoshikane, T. Tsuritani, I. Morita, M. Suzuki
41st European Conference on Optical Communication (ECOC2015) Vol. PDP.3.2 2015/09 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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Ultra-long-haul high-capacity super-Nyquist-WDM transmission experiment using multi-core fibers
Koji Igarashi, Takehiro Tsuritani, Itsuro Morita, Masatoshi Suzuki
IEEE Journal of Lightwave Technology Vol. 33 No. 5 p. 1027-1036 2015/03/01 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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114 Space-Division-Multiplexed Transmission over 9.8-km Weakly-Coupled-6-Mode Uncoupled-19-Core Fibers
K. Igarashi, D. Souma, Y. Wakayama, K. Takeshima, Y. Kawaguchi, T. Tsuritani, I. Morita, M. Suzuki
Conference on Optical Fiber Communication (OFC 2015) Vol. Th5C.4 2015/03 Research paper (international conference proceedings)
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1-Exabit/s×km Super-Nyquist-WDM Multi-Core-Fiber Transmission
Koji Igarashi, T. Tsuritani, I. Morita
40th European Conference on Optical Communication (ECOC2014) Vol. Mo.3.3.1 2014/09 Research paper (international conference proceedings)
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Super-Nyquist-WDM transmission over 7,326-km seven-core fiber with capacity-distance product of 1.03 Exabit/s.km
Koji Igarashi, Takehiro Tsuritani, Itsuro Morita, Yukihiro Tsuchida, Koichi Maeda, Masateru Tadakuma, Tsunetoshi Saito, Kengo Watanabe, Katsunori Imamura, Ryuichi Sugizaki, Masatoshi Suzuki
Optics Express Vol. 22 No. 2 p. 1220-1228 2014/01/27 Research paper (international conference proceedings)
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1.03-Exabit/s km Super-Nyquist-WDM transmission over 7,326-km seven-core fiber
K. Igarashi, T. Tsuritani, I. Morita, Y. Tsuchida, K. Maeda, M. Tadakuma, T. Saito, K. Watanabe, K. Imamura, R. Sugizaki, M. Suzuki
39th European Conference on Optical Communication (ECOC2013) Vol. PD3.E.3 2013/09 Research paper (international conference proceedings)
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High-sensitive optoelectronic clock recovery circuit featuring GVD-independent operation
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
32nd European Conference on Optical Communication (ECOC2006) Vol. Post deadline paper Th4.3.2 2006/09 Research paper (international conference proceedings)
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Reduction of fiber four-wave mixing generated from modulated lights by inserting dispersive elements
Ayano Inoue, Koji Igarashi, Shigehiro Takasaka, Kyo Inoue
IEICE Transactions on Communications p. 1-9 2024 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
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Joint Channel, CFO, and Data Estimation via Bayesian Inference for Multi-User MIMO-OFDM Systems
Kenta Ito, Takumi Takahashi, Koji Ishibashi, Koji Igarashi, Shinsuke Ibi
IEEE Transactions on Wireless Communications p. 1-1 2024 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
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Nonlinear interaction between non-orthogonally polarization-multiplexed signals in fiber transmission with polarization-dependent loss
Kyo Inoue, Koji Igarashi
Optics Continuum Vol. 2 No. 10 p. 2225-2225 2023/10/15 Research paper (scientific journal)
Publisher: Optica Publishing Group
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Level Allocation of Four-Level Pulse-Amplitude Modulation Signal in Optically Pre-Amplified Receiver Systems
Hiroki Kawahara, Koji Igarashi, Kyo Inoue
IEICE Transactions on Communications Vol. E106.B No. 8 p. 652-659 2023/08 Research paper (scientific journal)
Publisher: Institute of Electronics, Information and Communications Engineers (IEICE)
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AoA Estimation-Aided Bayesian Receiver Design via Bilinear Inference for mmWave Massive MIMO
Kenta Ito, Takumi Takahashi, Koji Igarashi, Shinsuke Ibi, Seiichi Sampei
ICC 2023 - IEEE International Conference on Communications 2023/05/28 Research paper (international conference proceedings)
Publisher: IEEE
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Nonlinear wave equation for wavelength/polarization multiplexed signals in fiber transmission
Kyo Inoue, Koji Igarashi
Optics Continuum Vol. 2 No. 6 p. 1331-1331 2023/05/22 Research paper (scientific journal)
Publisher: Optica Publishing Group
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Real-time 6-Mode 19-Core Fiber Transmission
S. Beppu, M. Kikuta, D. Soma, Y. Yaegashi, K. Igarashi, M. Shigihara, K. Aizawa, N. Yoshikane, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2023) Vol. Tu3E.5 2023/03 Research paper (international conference proceedings)
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Nonlinear Fiber Transmission of Compressed Shaping Signals
T. Yoshida, T. Inoue, K. Igarashi, M. Binkai, Y. Kohishi, N. Suzuki, M. Karlsson, E. Agrell
48th European Conference on Optical Communication (ECOC2022) Vol. Mo3D.6 2022/09 Research paper (international conference proceedings)
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Low-Complexity Symbol Demapping for Multidimensional Multilevel Coded Modulation
T. Yoshida, K. Igarashi, M. karlsson, E. Agrell
48th European Conference on Optical Communication (ECOC2022) Vol. We3C.1 2022/09 Research paper (international conference proceedings)
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Complex field measurement of optical frequency combs over 100-GHz bandwidth using a spectrally-slicing-and-synthesizing method
Y. Shimizu, K. Igarashi
27th Optoelectronics and Communications Conference (OECC2022) Vol. WB3-5 2022/07 Research paper (international conference proceedings)
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Soft-decision FEC Designed for Optically Preamplified PAM4 Direct Detection
K. Igarashi, T. Takahashi, S. Sampei, K. Inoue
27th Optoelectronics and Communications Conference (OECC2022) Vol. TuB1-4 2022/07 Research paper (international conference proceedings)
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Potts model solver based on hybrid physical and digital architecture
Kensuke Inaba, Takahiro Inagaki, Koji Igarashi, Shoko Utsunomiya, Toshimori Honjo, Takuya Ikuta, Koji Enbutsu, Takeshi Umeki, Ryoichi Kasahara, Kyo Inoue, Yoshihisa Yamamoto, Hiroki Takesue
Communications Physics Vol. 5 2022/05/31 Research paper (scientific journal)
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Analysis of Signal Distribution in ASE-Limited Optical On-Off Keying Direct-Detection Systems
Hiroki KAWAHARA, Kyo INOUE, Koji IGARASHI
IEICE Transactions on Communications Vol. E104.B No. 11 p. 1386-1394 2021/11/01 Research paper (scientific journal)
Publisher: Institute of Electronics, Information and Communications Engineers (IEICE)
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Measurement of Laser Phase Noise for Ultra-Long Period of 0.8 Seconds With 800-ps Temporal Resolution Using Optical Coherent Detection With FPGA-Implemented Data Acquisition
K. Igarashi, H. Kiwata, M. Kikuta, M. Shigihara
IEEE Jorunal of Lightwave Technology Vol. 39 No. 20 p. 6539-6546 2021/10 Research paper (scientific journal)
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Real-time MIMO DSP in Mode-division Multiplexed Transmission
K. Igarashi
EXAT2021 Vol. W1.4 2021/10 Research paper (international conference proceedings)
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Compressed shaping: Concept and FPGA demonstration
T. Yoshida, K. Igarashi, M. Karlsson, E. Agrell
IEEE Journal of Lightwave Technology Vol. 39 No. 17 p. 5412-5422 2021/09 Research paper (scientific journal)
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Mode-multiplexed 16QAM transmission over 60-km coupled four-core fibres using real-time MIMO-DSP with high-accuracy frequency offset estimation
S. Beppu, M. Kikuta, K. Igarashi, H. Mukai, M. Shigihara, Y. Saito, D. Soma, H. Takahashi, N. Yoshikane, T. Tsuritani
European Conference on Optical Communication (ECOC2021) Vol. We1C2.3 2021/09 Research paper (international conference proceedings)
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Real-time Transoceanic Coupled 4-core Fiber Transmission
S. Beppu, M. Kikuta, K. Igarashi, H. Mukai, M. Shigihara, Y. Saito, D. Soma, H. Takahashi, N. Yoshikane, I. Morita, M. Suzuki, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2021) Vol. F3B.4 2021/03 Research paper (international conference proceedings)
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Real-time MIMO-DSP Technologies for SDM Systems
S. Beppu, K. Igarashi, M. Kikuta, H. Mukai, M. Shigihara, Y. Saito, D. Soma, H. Takahashi, N. Yoshikane, I. Morita, T. Tsuritani, M. Suzuki
Conference on Optical Fiber Communication (OFC 2021) Vol. W7D.4 2021/03 Research paper (international conference proceedings)
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FPGA implementation of hierarchical subcarrier rate and distribution matching for up to 1.032 Tb/s or 262144-QAM
T. Yoshida, K. Igarashi, Y. Konishi, M. Karlsson, E. Agrell
Conference on Optical Fiber Communication (OFC 2021) Vol. Tu6D.4 2021/03 Research paper (international conference proceedings)
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Recent Progress of Real-time Space Division Multiplexed Techniques in Optical Fiber Transmission
K. Igarashi
2020 International Conference on Emerging Technologies for Communications (ICETC2020) Vol. IA3-2 2020/11 Research paper (international conference proceedings)
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Ultra-long-time (0.8 s) characterization of laser phase noise with high temporal resolution (800 ps) based on heterodyne reception with FPGA data acquisition,
H. Kiwata, M. Kikuta, M. Shigihara, K. Igarashi
46th European Conference on Optical Communication (ECOC2020) Vol. Tu2D-7 2020/11 Research paper (international conference proceedings)
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Sparse-Dense MLC for Peak Power Constrained Channels
T. Yoshida, K. Igarashi, M. Karlsson, Magnus, E. Agrell
46th European Conference on Optical Communication (ECOC2020) Vol. Mo2D-5 2020/11 Research paper (international conference proceedings)
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Required and Received SNRs in Coded Modulation
T. Yoshida, K. Igarashi, M. Binkai, S. Chikamori, M. Mazur, J. Schroeder, K. Matsuda, S. Koshikawa, N. Suzuki, M. Karlsson, E. Agrell
46th European Conference on Optical Communication (ECOC2020) Vol. Mo2D-4 2020/11 Research paper (international conference proceedings)
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High-speed (800 ps) and ultra-long-period (0.8 sec) characterization of laser phase noise by heterodyne detection with FPGA-implemented data acquisition
H. Kiwata, M. Kikuta, M. Shigihara, Koji Igarashi
Signal Processing to Photonics Communications (SPPCom2020) Vol. SpM3I.4 2020/07 Research paper (international conference proceedings)
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FPGA Implementation of MIMO DSP in Weakly-coupled Few-mode Fiber Transmission
Koji Igarashi, S. Beppu, T. Tsuritani
IEEE Photonics Society Summer Topicals Meeting Series 2020 (SUM2020) Vol. WD4.1 2020/07 Research paper (international conference proceedings)
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Real-Time Implementation of Adaptive MIMO Equalization with Fast Carrier-Phase Tracking
Koji Igarashi, S. Beppu, M. Kikuta, D. Soma, Y. Saito, T. Tsuritani
Signal Processing to Photonics Communications (SPPCom2020) Vol. SpTu1I.3 2020/07 Research paper (international conference proceedings)
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Real-time strongly-coupled 4-core fiber transmission
S. Beppu, Koji Igarashi, H. Mukai, M. Kikuta, M. Shigihara, D. Soma, T. Tsuritani, I. Morita
Conference on Optical Fiber Communication (OFC 2020) Vol. Th3H.2 2020/03 Research paper (international conference proceedings)
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Spectrally Slicing Coherent Optical Spectrum Analyzer for Measuring Complex Field Waveforms of Optical QAM Signals
Y. Kawabata, N. Urakawa, K. Kinoshita, Koji Igarashi
Conference on Optical Fiber Communication (OFC 2020) Vol. W4A.1 2020/03 Research paper (international conference proceedings)
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Statistics of mode couplings induced by concatenated multiple connections in weakly-coupled few-mode fibers
Koji Igarashi, Gen Kawabata
Optics Communications Vol. 467 No. 125685 2020/03 Research paper (scientific journal)
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Channel Compensation and CPR for PDM System Based on Channel Hardening Effect
Seiji Tanaka, Takumi Takahashi, Shinsuke Ibi, Koji Igarashi, Seiichi Sampei
Asia Communications and Photonics Conference (ACP2019) Vol. M4A.13 2019/11 Research paper (international conference proceedings)
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Real-time Optical Coherent MIMO Receiver in Weakly-coupled Ten-mode Multiplexed Transmission
Koji Igarashi, S. Beppu, M. Kikuta, Y. Saito, D. Soma, T. Tsuritani
European Conference on Optical Communication (ECOC2019) Vol. W.2.A.3 2019/09 Research paper (international conference proceedings)
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Signal Processing for Ultra-dense WDM/SDM Transmission Systems
Koji Igarashi
2018 IEEE Photonics Conference (IPC2018) Vol. MA1.3 2019/09 Research paper (international conference proceedings)
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Signal Processing for Mode Multiplexed Transmission in the Optical Domain and Digital Domain
Koji Igarashi
Photonics in Switching and Computing (PSC2018) Vol. Workshop 3 2019/09 Research paper (international conference proceedings)
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Reduction of Crosstalk Influence in a 7-Core Multicore Fiber by Frequency Interleave
S. Orii, K. Inoue, Koji Igarashi
IEICE Transactions on Communications Vol. E102B No. 8 p. 1590-1594 2019/08 Research paper (scientific journal)
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EXIT Chart-Aided Design of LDPC Codes for Pilot-Assisted Direct Detection with Turbo Equalizer for Optical Fiber Short-Reach Transmissions
N. Osawa, S. Ibi, K. Igarashi, S. Sampei
IEICE Trans. Commun. Vol. E102-B No. 7 p. 1301-1312 2019/07/01 Research paper (scientific journal)
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Real-time DSP for Adaptive FIR filters Based on LMS Algorithm
M. Kikuta, S. Beppu, T. Nagai, Y. Saito, T. Tsuritani, Koji Igarashi
24th Optoelectronics and Communications Conference (OECC2019) Vol. TuB2-3 2019/07 Research paper (international conference proceedings)
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Numerical Evaluation of Modal Crosstalk Statistics in Multiple Connectors of Weakly-coupled 10-mode Fibers
Gen Kawabata, Koji Igarashi
24th Optoelectronics and Communications Conference (OECC2019) Vol. ThG3-3 2019/07 Research paper (international conference proceedings)
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Constellation Monitor of QPSK Optical Signals Based on Spectrally-sliced Coherent Optical Spectrum Analyzers
Koji Igarashi, Naoki Urakawa
Optoelectronics and Communications Conference (OECC2019) Vol. ThC2-4 2019/07 Research paper (international conference proceedings)
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Generation efficiency of four-wave mixing for phase-shift keying signal light
Kyo Inoue, Koji Igarashi
IEICE Transaction on Communications Vol. E102-B No. 5 p. 1005-1010 2019/05 Research paper (scientific journal)
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Bit-error-rate degradation due to inter-channel crosstalk of different signal format
Naruki Shinohara, Koji Igarashi, Kyo Inoue
IEICE Transaction on Communications Vol. E102-B No. 5 p. 1000-1004 2019/05 Research paper (scientific journal)
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Simplified Iterative Decoder for Polybinary-Shaped Optical Signals in Super-Nyquist Wavelength Division Multiplexed Systems
S. Yuan, Koji Igarashi
IEICE Transactions on Communications Vol. E102.B No. 4 p. 818-823 2019/04 Research paper (scientific journal)
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Mode-dependent Probabilistic Shaping for Highly-efficient Weakly Coupled 10-mode Fiber Transmission
S. Beppu, D. Soma, Y. Wakayama, S. Sumita, Koji Igarashi, H. Takahashi, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2019) Vol. M2H.2 2019/03 Research paper (international conference proceedings)
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MAP Decoder for Nonlinear Compensation in WDM DP-QPSK Systems
S. Yuan, Koji Igarashi
Asia Communications and Photonics Conference (ACP2018) Vol. S4C.6 2018/10 Research paper (international conference proceedings)
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266.1-Tbit/s Transmission Over 90.4-km 6-Mode Fiber With Inline Dual C+L-Band 6-Mode EDFA
Yuta Wakayama, Daiki Soma, Shohei Beppu, Seiya Sumita, Koji Igarashi, Takehiro Tsuritani
IEEE Journal of Lightwave Technol. Vol. 37 No. 2 p. 404-410 2018/10 Research paper (scientific journal)
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Effective area measurement of few-mode fiber using far field scan technique with Hankel transform generalized for circularly-asymmetric mode
Tetsuya Hayashi, Yoshiaki Tamura, Takuji Nagashima, Kazuhiro Yonezawa, Toshiki Taru, Koji Igarashi, Daiki Soma, Yuta Wakayama, Takehiro Tsuritani
Optics Express Vol. 26 No. 9 p. 11137-11146 2018/04/30 Research paper (scientific journal)
Publisher: OSA - The Optical Society
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266.1-Tbit/s repeatered transmission over 90.4-km 6-mode fiber using dual C+L-band 6-mode EDFA
Yuta Wakayama, Daiki Soma, Shohei Beppu, Seiya Sumita, Koji Igarashi, Takehiro Tsuritani
Conference on Optical Fiber Communication (OFC 2018) Vol. W4C.1 2018/03 Research paper (international conference proceedings)
Publisher: OSA - The Optical Society
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Low-loss and low-crosstalk all-fiber-based six-mode multiplexer and demultiplexer for mode-multiplexed QAM signals in C-band
Koji Igarashi, Yuta Wakayama, Daiki Soma, Takehiro Tsuritani, Itsuro Morita, Kyung Jun Park, Jaekwon Ko, Byoung Yoon Kim
Conference on Optical Fiber Communication (OFC 2018) Vol. 2018 2018/03 Research paper (international conference proceedings)
Publisher: OSA - The Optical Society
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An iterative soft interference cancellation for pilot-assisted optical-OFDM with LDPC code optimized by EXIT chart
Noboru Osawa, Shinsuke Ibi, Koji Igarashi, Seiichi Sampei
Conference on Optical Fiber Communication (OFC 2018) Vol. Tu3C.4 2018/03 Research paper (international conference proceedings)
Publisher: OSA - The Optical Society
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All-fiber-based selective mode multiplexer and demultiplexer for weakly-coupled mode-division multiplexed systems
Koji Igarashi, Kyung Jun Park, Takahiro Tsuritani, Itsuro Morita, Byoung Yoon Kim
OPTICS COMMUNICATIONS Vol. 408 p. 58-62 2018/02 Research paper (scientific journal)
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Iterative decoding between feed-forward carrier recovery and FEC decoding to compensate for laser phase noise
Shuai Yuan, Koji Igarashi
2017 Opto-Electronics and Communications Conference, OECC 2017 and Photonics Global Conference, PGC 2017 Vol. 2017- p. 1-3 2017/11/17 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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Experimental characterization of step-index few-mode fiber for weakly-coupled 10-mode-multiplexed transmission
Yuta Wakayama, Daiki Soma, Koji Igarashi, Hidenori Taga, Takehiro Tsuritani
2017 Opto-Electronics and Communications Conference, OECC 2017 and Photonics Global Conference, PGC 2017 Vol. 2017- p. 1-3 2017/11/17 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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Improvement on Post-FEC BER Performance by Iterative Decoding Between a Feed-forward Carrier-Phase Estimator and an FEC Decoder
S. Yuan, K. Igarashi
Asia Communications and Photonics Conference (ACP2017) Vol. S3B.6 2017/11 Research paper (international conference proceedings)
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Suppression of IQ modulation error based on single-sideband modulation to generate ultra-high order QAM optical signals
Koji Igarashi
Asia Communications and Photonics Conference (ACP2017) Vol. M2C.1 2017/11 Research paper (international conference proceedings)
Publisher: OSA - The Optical Society
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Bit-Error Ratio Performance Improvement Using Iterative Decoding for Polybinary-Shaped Super-Nyquist Wavelength Division Multiplexed Signals
Shuai Yuan, Koji Igarashi, Takehiro Tsuritani, Itsuro Morita
IEEE Journal of Lightwave Technology Vol. 35 No. 21 p. 4605-4612 2017/11 Research paper (scientific journal)
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Dual C+L-Band Six-Mode Optical Amplifier with Widely Erbium-Doped Fibre
Yuta Wakayama, Daiki Soma, Koji Igarashi, Hidenori Taga, Takehiro Tsuritani
43rd European Conference on Optical Communication (ECOC2017) Vol. W.2.F 2017/09 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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257-Tbit/s Partial MIMO-based 10-Mode C+L-band WDM Transmission over 48-km FMF
Daiki Soma, Shohei Beppu, Yuta Wakayama, Yu Kawaguchi, Koji Igarashi, Takehiro Tsuritani
43rd European Conference on Optical Communication (ECOC2017) Vol. M.2.E 2017/09 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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What is the best fibre for the development of space-division multiplexing systems? Topics: SDM Transmission Experiments
Koji Igarashi
43rd European Conference on Optical Communication (ECOC2017) Vol. workshop 2017/09 Research paper (international conference proceedings)
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Adaptive equalization combined with maximum likelihood decoder for trellis code modulation based on high-order QAM signals
Koji Igarashi
22nd Optoelectronics and Communications Conference (OECC2017) Vol. P3-030 2017/07 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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Partial MIMO-based 10-Mode-Multiplexed Transmission over 81km Weakly-coupled Few-mode Fiber
D. Soma, Y. Wakayama, Koji Igarashi, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2017) Vol. M2D.4 2017/03 Research paper (international conference proceedings)
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Making the Case for SDM in 2027
Koji Igarashi, T. Kobayashi, T. Hayashi, T. Sakamoto, K. Imamura
Conference on Optical Fiber Communication (OFC 2017) Vol. workshop 2017/03 Research paper (international conference proceedings)
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Six-Mode 19-Core Fiber with 114 Spatial Modes for Weakly-Coupled Mode-Division-Multiplexed Transmission
Tetsuya Hayashi, Takuji Nagashima, Kazuhiro Yonezawa, Yuta Wakayama, Daiki Soma, Koji Igarashi, Takehiro Tsuritani, Toshiki Taru, Takashi Sasaki
IEEE Journal of Lightwave Technology Vol. 35 No. 4 p. 748-754 2017/02/15 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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Ultra-high Capacity Transmission Based on Ultra-dense WDM/SDM Techniques
Koji Igarashi, T. Tsuritani, I. Morita
Asia Communications and Photonics Conference (ACP2016) Vol. AF1D.3 2016/11 Research paper (international conference proceedings)
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665 and 947b/s/Hz Ultra-highly Aggregate-Spectral-Efficient SDM/WDM Transmission over 6-Mode 19-Core Fibre Using DP-16QAM/64QAM signals
D. Soma, Y. Wakayama, S. Beppu, Koji Igarashi, T. Tsuritani, H. Taga, I. Morita, M. Suzuki
42nd European Conference on Optical Communication (ECOC2016) Vol. Th.3.C.2 2016/09 Research paper (international conference proceedings)
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Novel 6-Mode Fibre Amplifier with Large Erbium-Doped Area for Differential Modal Gain Minimization
Y. Wakayama, Koji Igarashi, D. Soma, H. Taga, T. Tsuritani
42nd European Conference on Optical Communication (ECOC2016) Vol. M.2.A.3 2016/09 Research paper (international conference proceedings)
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Improvement on FEC performance by Turbo Equalization for Super-Nyquist WDM systems
S. Yuan, Koji Igarashi, T. Tsuritani, I. Morita
42nd European Conference on Optical Communication (ECOC2016) Vol. W.2.C.4 2016/09 Research paper (international conference proceedings)
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Polybinary Shaping for Highly-Spectral-Efficient Super-Nyquist WDM QAM Signals
Koji Igarashi, T. Tsuritani, I. Morita
IEEE Journal of Lightwave Technol. Vol. 34 No. 8 p. 1724-1731 2016/08 Research paper (scientific journal)
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Ultra-dense space division multiplexing technologies towards multi-Peta bit/s optical transmission
Masatoshi Suzuki, Daiki Soma, Koji Igarashi, Yuta Wakayama, Koki Takeshima, Yu Kawaguchi, Noboru Yoshikane, Takehiro Tsuritani, Itsuro Morita
18th International Conference on Transparent Optical Networks (ICTON2016) Vol. Mo.C1.2 2016/07 Research paper (international conference proceedings)
Publisher: IEEE Computer Society
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Turbo Equalization with 20%-overhead Turbo Code in Super-Nyquist WDM Systems
S. Yuan, Koji Igarashi, T. Tsuritani, I. Morita
Signal Processing in Photonic Communications 2016 (SPPCom2016) Vol. SpW2G.7 2016/07 Research paper (international conference proceedings)
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Weakly-coupled FMF Transmission for Reduction of MIMO Complexity
D. Soma, Y. Wakayama, Koji Igarashi, T. Tsuritani
Summer Topicals Meeting Series 2016 (SUM2016) Vol. TuE2.2 2016/07 Research paper (international conference proceedings)
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Turbo Equalization for Duobinary-shaped Signals in Super-Nyquist WDM Systems
S. Yuan, Koji Igarashi
21st Optoelectronics and Communications Conference (OECC2016) Vol. TuB4-4 2016/07 Research paper (international conference proceedings)
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Bit-error Rate Performance of Six-mode-multiplexed DP-64QAM signals
Koji Igarashi, T. Tsuritani, I. Morita
IEEE Summer Topicals Meeting Series 2016 (SUM2016) Vol. WE3.2 p. 232-233 2016/07 Research paper (international conference proceedings)
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Ultra-high-capacity Transmission over Few-mode Multi-core Fibers
Koji Igarashi, T. Tsuritani, I. Morita
21st Optoelectronics and Communications Conference (OECC2016) Vol. S2-5 2016/07 Research paper (international conference proceedings)
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Intermediate Mode Interchange for Reduction of Differential Mode-Group Delay in Weakly-Coupled 6-Mode Fiber Transmission Line
Y. Wakayama, D. Soma, Koji Igarashi, H. Taga, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2016) Vol. M3E.6 2016/03 Research paper (international conference proceedings)
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6-mode 19-core Fiber for Weakly-coupled Mode-multiplexed Transmission over Uncoupled Cores
T. Hayashi, T. Nagashima, K. Yonezawa, T. Sasaki, Y. Wakayama, D. Soma, Koji Igarashi, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2016) Vol. W1F.4 2016/03 Research paper (international conference proceedings)
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51.1-Tbit/s MCF Transmission over 2520 km Using Cladding-Pumped Seven-Core EDFAs
Koki Takeshima, Takehiro Tsuritani, Yukihiro Tsuchida, Koichi Maeda, Tsunetoshi Saito, Kengo Watanabe, Toru Sasa, Katsunori Imamura, Ryuichi Sugizaki, Koji Igarashi, Itsuro Morita, Masatoshi Suzuki
IEEE Journal of Lightwave Technology Vol. 34 No. 2 p. 761-767 2016/01/15 Research paper (scientific journal)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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WDM/SDM transmission of 76 × 128-Gbit/s Nyquist-pulse-shaped DP-QPSK Signals over 4,200 km using cladding pumped 7-Core EDFA
K. Takeshima, T. Tsuritani, K. Igarashi, I. Morita, Y. Tsuchida, K. Maeda, T. Saito, K. Watanabe, T. Sasa, K. Imamura, R. Sugizaki
2015 Opto-Electronics and Communications Conference, OECC 2015 Vol. JThA.73 2015/11/30 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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DMD Measurement of 114-SDM Transmission Fibre Using Low-Coherence Interferometry with Digital Holographic Processing
Y. Wakayama, H. Taga, Koji Igarashi, T. Tsuritani
41st European Conference on Optical Communication (ECOC2015) Vol. P.1.19 2015/09 Research paper (international conference proceedings)
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114 Space-Division-Multiplexed WDM Transmission Using 6-mode 19-core Fibers
Koji Igarashi, T. Tsuritani, I. Morita
2015 IEEE Photonics Conference (IPC2015) Vol. MJ2.1 2015/09 Research paper (international conference proceedings)
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Experimental Study on Polybinary-Pulse-Shaped QAM Signals for Highly-Spectral-Efficient Super-Nyquist-WDM Systems
Koji Igarashi, T. Tsuritani, I. Morita
41st European Conference on Optical Communication (ECOC2015) Vol. Mo.3.3.6 2015/09 Research paper (international conference proceedings)
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Bit-error-rate improvement of binary phase-shift keying signals with an optoelectronic regenerator based on the feed-forward control of a LiNbO3 intensity modulator
Shohei Okada, Koji Igarashi, Kyo Inoue
Optical Fiber Technology Vol. 24 p. 49-55 2015/08 Research paper (scientific journal)
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High-capacity Ultra-long-haul Transmission Experiments Using Multi-core Fibers
Koji Igarashi, K. Takeshima, T. Tsuritani, I. Morita, M. Suzuki
International Symposium on extremely advanced transmission technology (EXAT 2015) Vol. W3.1 2015/07 Research paper (international conference proceedings)
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Super-Nyquist-WDM Technique for Ultra-Long-Haul High-Capacity Optical Fiber Transmission Systems
Koji Igarashi, T. Tsuritani, I. Morita, M. Suzuki
20th Optoelectronics and Communications Conference (OECC2015) Vol. JMoA.22 2015/06 Research paper (international conference proceedings)
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Ultra-Long-Haul High-Capacity Multi-Core Fiber Transmission with Capacity-Distance Product over 1 Exabit/s·km
Koji Igarashi
2015 EMN optoelectronics Meeting Vol. D18 2015/04 Research paper (international conference proceedings)
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51.1-Tbit/s MCF Transmission over 2,520 km Using Cladding Pumped 7-core EDFAs
K. Takeshima, T. Tsuritani, Y. Tsuchida, K. Maeda, T. Saito, K. Watanabe, T. Sasa, K. Imamura, R. Sugizaki, Koji Igarashi, I. Morita, M. Suzuki
Conference on Optical Fiber Communication (OFC 2015) Vol. W3G.1 2015/03 Research paper (international conference proceedings)
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Selective mode multiplexer based on phase plates and Mach-Zehnder interferometer with image inversion function
Koji Igarashi, Daiki Souma, Koki Takeshima, Takehiro Tsuritani
Optics Express Vol. 23 No. 1 p. 183-194 2015/01/12 Research paper (scientific journal)
Publisher: Optical Society of American (OSA)
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Frequency interleave in multicore fiber transmission systems for reducing influence of inter-core crosstalk
S. Okada, Koji Igarashi, Kyo Inoue
Optical Fiber Technology Vol. 27 p. 17-23 2015 Research paper (scientific journal)
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Trans-oceanic class ultra-long-haul transmission using multi-core fiber
Itsuro Morita, Koji Igarashi, Hidenori Takahashi, Takehiro Tsuritani, Masatoshi Suzuki
OPTICS EXPRESS Vol. 22 No. 26 p. 31761-31773 2014/12 Research paper (scientific journal)
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Super-Nyquist-WDM Multi-core Fiber Transmission with Capacity-Distance Product over 1 Exabit/s·km
Koji Igarashi
9th International Workshop on Optical Signal Processing and Optical Switching (IWOO2014) Vol. 25 2014/10 Research paper (international conference proceedings)
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Degenerate Modes Multiplexer/Demultiplexer using Mach-Zehnder Interferometer with Image Inversion
D. Souma, K. Takeshima, Koji Igarashi, T. Tsuritani
40th European Conference on Optical Communication (ECOC 2014) Vol. We.1.1.6 2014/09 Research paper (international conference proceedings)
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Selective Mode Conversion Using Phase Plates for 10-Mode Fiber
Koji Igarashi, D. Souma, T. Tsuritani
40th European Conference on Optical Communication (ECOC2014) Vol. P.1.2 2014/09 Research paper (international conference proceedings)
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Performance evaluation of selective mode conversion based on phase plates for a 10-mode fiber
Koji Igarashi, D. Souma, T. Tsuritani, I. Morita
Optics Express Vol. 22 No. 17 p. 20881-20893 2014/08 Research paper (scientific journal)
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1-Exabit/s·km Super-Nyquist-WDM Transmission using Multi-Core Fibers
Koji Igarashi, T. Tsuritani, I. Morita
International Conference on Optical Internet (COIN2014) Vol. FB4-1 2014/08 Research paper (international conference proceedings)
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Effective area measurement of few-mode fiber using far field scan technique with Hankel transform generalized for circularly-asymmetric mode
Tetsuya Hayashi, Yoshiaki Tamura, Takuji Nagashima, Kazuhiro Yonezawa, Toshiki Taru, Koji Igarashi, Daiki Soma, Yuta Wakayama, Takehiro Tsuritani
Optics InfoBase Conference Papers 2014/07/21 Research paper (international conference proceedings)
Publisher: OSA - The Optical Society
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Optoelectronic Regeneration of Binary Phase-Shift Keying Optical Signals Based on a Feed-Forward Control of a LiNbO3 Intensity Modulator
S. Okada, S. Suwa, Koji Igarashi, Kyo Inoue
Optoelectronics and Communications Conference (OECC2014) Vol. TUPS1-19 2014/07 Research paper (international conference proceedings)
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1 Exabit/s·km Transmission with Multi-Core Fiber and Spectral Efficient Modulation Format
I. Morita, Koji Igarashi, T. Tsuritani
Optoelectronics and Communications Conference (OECC2014) Vol. TU5C-5 p. 316-318 2014/07 Research paper (international conference proceedings)
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Optical Pulse Shaping for Super-Nyquist WDM Transmission
Koji Igarashi
Signal Processing to Photonics Communications (SPPCom2014) Vol. ST4D.3 2014/07 Research paper (international conference proceedings)
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Long-haul transmission using multicore fibers
Hidenori Takahashi, Koji Igarashi, Takehiro Tsuritani
Conference on Optical Fiber Communication (OFC 2014) Vol. Tu2J.2 2014/03 Research paper (international conference proceedings)
Publisher: Institute of Electrical and Electronics Engineers Inc.
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Bit-Error Rate Performance of Super-Nyquist-WDM DP-QPSK Signals with Duobinary-Pulse Shaping
Koji Igarashi, Takehiro Tsuritani, Itsuro Morita
2014 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC) Vol. Th2A.18 2014 Research paper (international conference proceedings)
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Seven-core fiber with enlarged Aeff and full-C-band seven-core EDFA for 100-Tbit/s-class transoceanic transmission
K. Igarashi, K. Takeshima, T. Tsuritani, H. Takahashi, S. Sumita, I. Morita, Y. Tsuchida, M. Tadakuma, K. Maeda, T. Saito, K. Watanabe, K. Imamura, R. Sugizaki, M. Suzuki
39th European Conference on Optical Communication (ECOC2013) Vol. Mo.3.A.2 2013/09 Research paper (international conference proceedings)
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110.9-Tbit/s SDM transmission over 6,370 km using a full C-band seven-core EDFA
Koji Igarashi, Koki Takeshima, Takehiro Tsuritani, Hidenori Takahashi, Seiya Sumita, Itsuro Morita, Yukihiro Tsuchida, Masateru Tadakuma, Koichi Maeda, Tsunetoshi Saito, Kengo Watanabe, Katsunori Imamura, Ryuichi Sugizaki, Masatoshi Suzuki
Optics Express Vol. 21 No. 15 p. 18053-18060 2013/07/29 Research paper (scientific journal)
Publisher: Optical Society of American (OSA)
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Ultra-long-haul transmission using multicore fiber repeatered by multicore EDFA
Hidenori Takahashi, Koji Igarashi, Koki Takeshima, Takehiro Tsuritani, Itsuro Morita
18th Optoelectronics and Communications Conference (OECC2013) Vol. TuR1-5 2013/07 Research paper (international conference proceedings)
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Multicore erbium doped fiber amplifier with 5 THz bandwidth, high-gain and low NF
Yukihiro Tsuchida, Koichi Maeda, Jutaro Miura, Kengo Watanabe, Tsunetoshi Saito, Koji Igarashi, Takehiro Tsuritani, Itsuro Morita, Toshiharu Ito, Kiyoshi Fukuchi, Ryuichi Sugizaki
2013 IEEE Photonics Society Summer Topical Meeting Series p. 105-106 2013/07 Research paper (international conference proceedings)
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Comparison of DSP Equalizer Complexity between Strongly and Weakly Coupled Few Mode Fiber Transmission Systems
B. Inan, Koji Igarashi, B. Spinnler, T. Tsuritani, N. Hanik
18th Optoelectronics and Communications Conference (OECC2013) Vol. MR2-7 2013/07 Research paper (international conference proceedings)
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Higher-Order Mode Conversion Using Cascade Phase Plates
Koji Igarashi, T. Tsuritani, I. Morita
18th Optoelectronics and Communications Conference (OECC2013) Vol. MR2-3 2013/07 Research paper (international conference proceedings)
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Ultra-large capacity transmission over trans-oceanic distances with multi-core fibers and EDFAs
Masatoshi Suzuki, Hidenori Takahashi, Koji Igarashi, Koki Takeshima, Takehiro Tsuritani, Itsuro Morita
International Conference on Transparent Optical Networks (ICTON2013) 2013/06 Research paper (international conference proceedings)
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Influence of Channel Misalignment of Time-Interleaved DAC on Sensitivity Degradation in Coherent Optical Receivers
C. Han, Koji Igarashi, Kazuro Kikuchi
Conference on Optical Fiber Communication (OFC 2013) Vol. OTh1F.2 2013/03 Research paper (international conference proceedings)
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Comparison of Network Cost and Power Consumption Between a Single-Line-Rate Network and a Flexible-Bitrate Network in the Beyond-100-Gb/s Networks Era
N. Yoshikane, Koji Igarashi, T. Tsuritani
Conference on Optical Fiber Communication (OFC 2013) Vol. NW3E.4 2013/03 Research paper (international conference proceedings)
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Frequency Stabilization of Multiple Semiconductor Lasers for Nyquist-WDM Transmission Systems
Koji Igarashi, T. Tsuritani, I. Morita, Kazuhiro Katoh, Kazuro Kikuchi
Conference on Optical Fiber Communication (OFC 2013) Vol. OTu2I.6 2013/03 Research paper (international conference proceedings)
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First demonstration of MC-EDFA-repeatered SDM transmission of 40 × 128-Gbit/s PDM-QPSK signals per core over 6,160-km 7-core MCF
H. Takahashi, T. Tsuritani, E. L.T. De Gabory, T. Ito, W. R. Peng, K. Igarashi, K. Takeshima, Y. Kawaguchi, I. Morita, Y. Tsuchida, Y. Mimura, K. Maeda, T. Saito, K. Watanabe, K. Imamura, R. Sugizaki, M. Suzuki
Optics Express Vol. 21 No. 1 p. 789-795 2013/01/14 Research paper (scientific journal)
Publisher: Optical Society of American (OSA)
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Second-order PMD monitoring from adaptive FIR-filter tap coefficients in a digital coherent receiver
Md. S. Faruk, Y. Mori, C. Zhang, Koji Igarashi, Kazuro Kikuchi
Optical Fiber Communications Conference (OFC 2011) Vol. OWN3 2011/03 Research paper (international conference proceedings)
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Characterization of semiconductor-laser phase noise with digital coherent receivers
Kazuro Kikuchi, Koji Igarashi
Optical Fiber Communications Conference (OFC 2011) Vol. OML3 2011/03 Research paper (international conference proceedings)
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Bit-Error Rate Performance of Nyquist Wavelength-Division Multiplexed Quadrature Phase-Shift Keying Optical Signals
Koji Igarashi, Y. Mori, Kazuhiro Katoh, Kazuro Kikuchi
Conference on Optical Fiber Communication (OFC 2011) Vol. OMR6 2011/03 Research paper (international conference proceedings)
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Multi-impairment monitoring from adaptive finite-impulse-response filters in a digital coherent receiver
Md. Saifuddin Faruk, Yojiro Mori, Chao Zhang, Koji Igarashi, Kazuro Kikuchi
Optics Express Vol. 18 No. 26 p. 26929-26936 2010/12/20 Research paper (scientific journal)
Publisher: Optical Society of American (OSA)
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Continuously-tunable Optical Delay Line using PLC-based Optical FIR Filter
H. M. Nguyen, Koji Igarashi, K. Katoh, K. Kikuchi
Conference on Lasers and Electro-optics (CLEO 2010) Vol. CFE2 2010/05 Research paper (international conference proceedings)
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Equalization of nonlinear transmission impairments by maximum-likelihood- sequence estimation in digital coherent receivers
Md Khairuzzaman, Chao Zhang, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optics Express Vol. 18 No. 5 p. 4776-4782 2010/03/01 Research paper (scientific journal)
Publisher: Optical Society of American (OSA)
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Ultrafast digital coherent receiver based on parallel processing of decomposed frequency subbands
Chao Zhang, Yojiro Mori, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication, ECOC Vol. 1-2 2010 Research paper (international conference proceedings)
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Tunable optical equalizer for 40-Gbps intensity-modulated signal using PLC-based finite-impulse-response filter
Hoang Manh Nguyen, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication, ECOC Vol. 1-2 2010 Research paper (international conference proceedings)
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Straight-line 1,073-km transmission of 640-Gbit/s dual-polarization QPSK signals on a single carrier
C. Zhang, Y. Mori, M. Usui, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication (ECOC 2009) Vol. PD2.8 2009/09 Research paper (international conference proceedings)
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200-km transmission of 100-Gbit/s 32-QAM dual-polarization signals using a digital coherent receiver
Y. Mori, C. Zhang, M. Usui, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication (ECOC 2009) Vol. 8.4.6 2009/09 Research paper (international conference proceedings)
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Transmission of 160-Gbit/s QPSK signals on a single carrier over 1,000 km using digital coherent receivers
C. Zhang, Y. Mori, M. Usui, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication (ECOC 2009) Vol. 10.3.6 2009/09 Research paper (international conference proceedings)
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Bandwidth-and wavelength-tunable comb filter using PLC-based optical transversal filter
H. M. Nguyen, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Conference on Lasers and Electro-optics (CLEO 2009) Vol. CFV1 2009/05 Research paper (international conference proceedings)
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Phase-noise tolerance of optical 16-QAM signals demodulated with decision-directed carrier-phase estimation
Y. Mori, C. Zhang, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optical Fiber Communication Conference (OFC 2009) Vol. OWG7 2009/03 Research paper (international conference proceedings)
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Demodulation of 1.28-Tbit/s Polarization-multiplexed 16-QAM Signals on a Single Carrier with Digital Coherent Receiver
C. Zhang, Y. Mori, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optical Fiber Communication Conference (OFC 2009) Vol. OTuG3 2009/03 Research paper (international conference proceedings)
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Unrepeated 200-km transmission of 40-Gbit/s 16-QAM signals using digital coherent receiver
Yojiro Mori, Chao Zhang, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optics Express Vol. 17 No. 3 p. 1435-1441 2009/02/02 Research paper (scientific journal)
Publisher: Optical Society of America (OSA)
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Ultrafast operation of digital coherent receivers using their time-division demultiplexing function
Chao Zhang, Yojiro Mori, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Journal of Lightwave Technology Vol. 27 No. 3 p. 224-232 2009/02/01 Research paper (international conference proceedings)
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PLC-based tunable optical equalizer for 40-Gbps intensity-modulated signal
Hoang Manh Nguyen, Koji Igarashi, Karuhiro Katoh, Kazuro Kikuchi
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest Vol. ThH4.3 2009 Research paper (international conference proceedings)
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Fiber-nonlinearity equalization by maximum-likelihood-sequence estimation (MLSE) in digital coherent receivers
Md Khairuzzaman, Chao Zhang, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
2009 14th OptoElectronics and Communications Conference, OECC 2009 Vol. TuK5 2009 Research paper (international conference proceedings)
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Optoelectronic 1:4 demultiplexing and clock recovery using dual-port LiNbO 3 intensity modulators
Shinsuke Nabeya, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
2009 14th OptoElectronics and Communications Conference, OECC 2009 Vol. TuJ4 2009 Research paper (international conference proceedings)
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Optoelectronic signal processing based on LiNbO3 modulators and its application to 160-Gbit/s systems
Koji Igarashi
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest Vol. ThH1-2 2009 Research paper (international conference proceedings)
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Optical signal processing by phase modulation and subsequent spectral filtering aiming at applications to ultrafast optical communication systems
Koji Igarashi, Kazuro Kikuchi
IEEE Journal on Selected Topics in Quantum Electronics Vol. 14 No. 3 p. 551-565 2008/05 Research paper (scientific journal)
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Demodulation of 640-Gbit/s Polarization- multiplexed OTDM QPSK Signals using a Digital Coherent Receiver
C. Zhang, Y. Mori, Koji Igarashi, Kazuro Kikuchi
Optical Fiber Communication Conference (OFC 2008) Vol. P6 2008/02 Research paper (international conference proceedings)
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Decision-feedback carrier-phase estimation for digital coherent optical receivers
Yojiro Mori, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
2008 Joint Conference of the Opto-Electronics and Communications Conference and the Australian Conference On Optical Fibre Technology, OECC/ACOFT 2008 2008 Research paper (international conference proceedings)
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Transmission of 40-Gbit/s 16-QAM Signal over 100-km standard single-mode fiber using digital coherent optical receiver
Yojiro Mori, Chao Zhang, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication, ECOC Vol. Tu.1.E.4 2008 Research paper (international conference proceedings)
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Demodulation of 480-Gbit/s 8PSK OTDM signal with diaital coherent receiver
Chao Zhang, Yojiro Mori, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
European Conference on Optical Communication, ECOC Vol. Mo.4.D.6 2008 Research paper (international conference proceedings)
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Unrepeated 200-km transmission of 40-gbit/s 16-QAM signals using digital coherent optical receiver
Yojiro Mori, Zhang Chao, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
2008 Joint Conference of the Opto-Electronics and Communications Conference and the Australian Conference On Optical Fibre Technology, OECC/ACOFT 2008 Vol. P-4 2008 Research paper (international conference proceedings)
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Demodulation of 320-Gbit/s optical quadrature phase-shift keying signal with digital coherent receiver having time-division demultiplexing function
Kazuro Kikuchi, Koji Igarashi, Yojiro Mori, Chao Zhang
OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference Vol. OTuO4 2008 Research paper (international conference proceedings)
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Generation of 10-GHz 2-ps optical pulse train over the C band based on an optical comb generator and its application to 160-Gbit/s OTDM systems
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi, Kazuhiro Imai, Motonobu Kourogi
European Conference on Optical Communication, ECOC Vol. Tu3.D.1 2008 Research paper (international conference proceedings)
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160-Gbit/s optical time-division demultiplexing based on cross-phase modulation in a 2-m-long dispersion-shifted Bi2O3 photonic crystal fiber
K. Igarashi, K. Katoh, K. Kikuchi, T. Nagashima, T. Hasegawa, S. Ohara, N. Sugimoto
Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series Vol. JTuC3 2007 Research paper (international conference proceedings)
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Suppression of ASE noise in the signal band by the spectral spread technique
K. Igarashi, K. Katoh, K. Kikuchi
OFC/NFOEC 2007 - Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007 Vol. JWA46 2007 Research paper (international conference proceedings)
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Optoelectronic time-division demultiplexing of 160-Gbit/s optical signal based on phase modulation and spectral filtering
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optics Express Vol. 14 No. 25 p. 845-851 2006/10 Research paper (scientific journal)
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Optoelectronic time-division demultiplexing of 160-Gbit/s signals based on phase modulation and spectral filtering
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
11st Optoelectronics and Communications Conference (OECC2006) Vol. 4F2-2 2006/07 Research paper (international conference proceedings)
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Optical pulse compression based on stationary rescaled pulse propagation in a comblike profiled fiber
Takashi Inoue, Hideaki Tobioka, Koji Igarashi, Shu Namiki
Journal of Lightwave Technology Vol. 24 No. 7 p. 2510-2522 2006/07 Research paper (scientific journal)
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Real-time all-optical waveform sampling using a passively mode-locked fiber laser as the sampling pulse source
T. Kiatchanog, Koji Igarashi, T. Tanemura, D. Wang, Kazuhiro Katoh, Kazuro Kikuchi
Optical Fiber Communication Conference (OFC2006) Vol. OWN1 2006/03 Research paper (international conference proceedings)
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Clock extraction from 160-Gbit/s signal using optoelectronic phase-locked loop based on optical phase modulation and spectral filtering
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optical Fiber Communication Conference (OFC2006) Vol. OTuB4 2006/03 Research paper (international conference proceedings)
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A high speed OTDM receiver of clock recovery and demultiplexing using bismuth oxide-based nonlinear fiber and erbium-doped bismuth oxide fiber
Ju Han Lee, Seiki Ohara, Tatsuo Nagashima, Tomoharu Hasegawa, Naoki Sugimoto, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006 Vol. CMT2 2006 Research paper (international conference proceedings)
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160-Gbit/s OTDM receiver with optoelectronic clock-recovery and demultiplexing functions based on phase modulation and spectral filtering
K. Igarashi, K. Katoh, K. Kikuchi
2006 European Conference on Optical Communications Proceedings, ECOC 2006 Vol. Th3.5.2 2006 Research paper (international conference proceedings)
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Optical time-division demultiplexer based on selective spectral shift and spectral filtering
K. Igarashi, K. Katoh, K. Kikuchi
Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006 Vol. CMAA1 2006 Research paper (international conference proceedings)
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Prescaled phase-locked loop using phase modulation and spectral filtering and its application to clock extraction from 160-Gbit/s optical-time-division multiplexed signal
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Optics Express Vol. 14 No. 9 p. 4087-4091 2006 Research paper (scientific journal)
Publisher: Optical Society of America (OSA)
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Clock recovery and demultiplexing of high-speed OTDM signal through combined use of Bismuth oxide nonlinear fiber and erbium-doped Bismuth oxide fiber
Ju Han Lee, Seiki Ohara, Tatsuo Nagashima, Tomoharu Hasegawa, Naoki Sugimoto, Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
IEEE Photonics Technology Letters Vol. 17 No. 12 p. 2658-2660 2005/12 Research paper (scientific journal)
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Generation of 10-GHz, 2-ps pulse train with high extinction ratio and low timing jitter from a continuous wave tunable over the entire C band
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
31st European Conference on Optical Communication (ECOC2005) Vol. Mo3.4.2 2005/09 Research paper (international conference proceedings)
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Nearly exact optical beat-to-soliton train conversion based on comb-like profiled fiber emulating a polynomial dispersion decreasing profile
Yasuyuki Ozeki, Shigehiro Takasaka, Takashi Inoue, Koji Igarashi, Jiro Hiroishi, Ryuichi Sugizaki, Misao Sakano, Shu Namiki
IEEE Photonics Technology Letters Vol. 17 No. 8 p. 1698-1700 2005/08 Research paper (scientific journal)
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Widely wavelength-tunable 40 GHz femtosecond pulse source based on compression of externally-modulated pulse using 1.4 km comb-like profiled fibre
K. Igarashi, H. Tobioka, M. Takahashi, T. Yagi, S. Namiki
Electronics Letters Vol. 41 No. 14 p. 797-798 2005/07/07 Research paper (scientific journal)
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Pedestal-free, nearly exact optical-beat-to-soliton train conversion based on comb-like profiled fiber emulating 5th order polynomial dispersion decreasing profile
Y. Ozeki, S. Takasaka, T. Inoue, Koji Igarashi, J. Hiroishi, R. Sugizaki, M. Sakano, S. Namiki
Conference on Lasers and Electro-Optics (CLEO2005) Vol. CWC5 2005/07 Research paper (international conference proceedings)
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Widely tunable 10-GHz picosecond optical pulse generator based on phase modulation, chirp compensation and nonlinear filtering
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Tenth Optoelectronics and Communications Conference (OECC2005) Vol. 6D3-5 2005/07 Research paper (international conference proceedings)
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5 - 500 MHz repetition-programmable low pedestal femtoseconulse source using comb-like profiled fiber
Koji Igarashi, H. Tobioka, A. Oguri, T. Akutsu, S. Namiki, M. Sakano, R. Kawahara, K. Okamura, Y. Aoyagi, N. Kagi
Conference on Lasers and Electro-Optics (CLEO2005) Vol. CTuCC4 2005/07 Research paper (international conference proceedings)
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Comb-like profiled fibre for efficient generation of high quality 160 GHz sub-picosecond soliton train
K. Igarashi, J. Hiroishi, T. Yagi, S. Namiki
Electronics Letters Vol. 41 No. 12 p. 688-690 2005/06/09 Research paper (scientific journal)
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Design of comb-like profiled fiber for efficient pulse compression based on stationary rescale pulse propagation
T. Inoue, H. Tobioka, Koji Igarashi, S. Namiki
Optical Fiber Communication Conference (OFC2005) Vol. JWA7 2005/03 Research paper (international conference proceedings)
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Widely tunable sub-picosecond compression of 40 GHz externally-modulateulse train using 1.4 km long comb-like profiled fiber
Koji Igarashi, H. Tobioka, M. Takahashi, J. Hiroishi, T. Yagi, M. Sakano, S. Namiki
Optical Fiber Communication Conference (OFC2005) Vol. JWA6 2005/03 Research paper (international conference proceedings)
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Ultra short pulse generation and reshaping using highly nonlinear fibers
S. Matsushita, S. Namiki, T. Inoue, A. Oguri, T. Akutsu, J. Shinozaki, Y. Ozeki, S. Takasaka, K. Igarashi, M. Sakano, T. Yagi
Proceedings of SPIE - The International Society for Optical Engineering Vol. 6019 2005 Research paper (international conference proceedings)
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Optical phase-locking of 160 GHz optical beat to 40 GHz optical pulse train using a three-electrode DFB-LD and a Si avalanche photodiode
Shigehiro Takasaka, Yasuyuki Ozeki, Koji Igarashi, Shu Namiki
IET Conference Publications Vol. 2005 No. 502 p. 799-800 2005 Research paper (international conference proceedings)
Publisher: Institution of Engineering and Technology
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A wavelength-tunable, 10-GHz, sub-500-fs optical pulse source based on square-wave-driven LiNbO3 modulator and comb-like profiled fiber
Y. Ozeki, K. Igarashi, A. Oguri, S. Takasaka, M. Sakano, S. Namiki
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest Vol. 2005 p. 1202-1203 2005 Research paper (international conference proceedings)
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Prescaled optoelectronic phase-locked loop using a highly sensitive phase comparator based on phase modulation and spectral filtering
Koji Igarashi, Kazuhiro Katoh, Kazuro Kikuchi
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS Vol. 2005 p. 695-696 2005 Research paper (international conference proceedings)
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Wideband tunable, low-noise 40 GHz RZ picoseconulse train generation using short comb-like profiled fiber
Koji Igarashi, M. Takahashi, J. Hiroishi, R. Sugizaki, S. Takasaka, T. Inoue, T. Yagi, S. Namiki
30th European Conference on Optical Communication (ECOC2004) Vol. Tu3.3.1 2004/09 Research paper (international conference proceedings)
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Wideband-tunable highly pure 40 GHz picosecond soliton train generation by short comb-like profiled fiber
Koji Igarashi, S. Takasaka, R. Miyabe, J. Hiroishi, R. Sugizaki, T. Yagi, S. Namiki
Conference on Lasers and Electro-Optics (CLEO2004) Vol. CFC1 2004/05 Research paper (international conference proceedings)
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Wavelength conversion characteristics of highly efficient fiberoptic four-wave mixer for 160 GHz picoseconulse train
Koji Igarashi, H. Tobioka, S. Takasaka, R. Miyabe, J. Hiroishi, T. Yagi, O. Aso, S. Namiki
Optical Fiber Communication Conference (OFC2004) Vol. TuC6 2004/02 Research paper (international conference proceedings)
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Investigation on Sub-20 fs Fiber-soliton Compression Performance of Dispersion-Flattened Fibers
Koji Igarashi, Satoshi Saito, Hiroyuki Nagai, Makoto Yoshida, Masato Kishi, Masahiro Tsuchiya
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers Vol. 43 No. 1 p. 132-136 2004 Research paper (scientific journal)
Publisher: Japan Society of Applied Physics
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Low-noise ultra-fast fiber parametric wavelength converter for 160 GHz sub-picojoule picosecond pulse train using low dispersion slope highly nonlinear fiber
H. Tobioka, Koji Igarashi, S. Takasaka, R. Miyabe, J. Hiroishi, R. Sugizaki, T. Yagi, O. Aso, S. Namiki
29th European Conference on Optical Communication (ECOC2003) Vol. We3.7.1 2003/09 Research paper (international conference proceedings)
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Pulse compression and noise characteristics of 160 GHz picoseconulse train in comb-like dispersion profiled fiber and short highly-nonlinear fiber
Koji Igarashi, S. Takasaka, T. Inoue, R. Miyabe, J. Hiroishi, T. Yagi, S. Namiki
29th European Conference on Optical Communication (ECOC2003) Vol. We3.7.3 2003/09 Research paper (international conference proceedings)
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Efficiency of highly nonlinear fiber in soliton converter for 40 Gbit/s 10,000 km fiber transmission
Koji Igarashi, S. Takasaka, T. Inoue, R. Miyabe, J. Hiroishi, T. Yagi, S. Namiki
Optical Amplifiers and Their Applications Topical Meeting (OAA2003) Vol. MD02 2003/07 Research paper (scientific journal)
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Ultra-highly pure 160 GHz sub-picosecond soliton train generation with average dispersion-managed comb-like dispersion profiled fiber using highly-nonlinear fiber
Koji Igarashi, R. Miyabe, J. Hiroishi, S. Takasaka, H. Tobioka, S. Matsushita, T. Yagi, S. Namiki
Conference on Lasers and Electro-Optics (CLEO2003) Vol. CMH7 2003/07 Research paper (international conference proceedings)
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Duration-tunable 100-GHz sub-picosecond soliton train generation through adiabatic Raman amplification in conjunction with soliton reshaping
Koji Igarashi, H. Tobioka, S. Takasaka, S. Matsushita, S. Namiki
Optical Fiber Communication Conference (OFC2003) Vol. TuB6 2003/03 Research paper (international conference proceedings)
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Fourth-order dispersion effect on generation of flat and broadband super-continuum in anomalous-dispersion-flattened fiber
Koji Igarashi, S. Saito, M. Kishi, Masahiro Tsuchiya
7th OptoElectronics and Communications Conference (OECC2002) Vol. Post deadline paper PD-2-3 2002/07 Research paper (scientific journal)
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Optimization of sub-picosecond EDF preamplifier dynamics for ultrashort soliton pulse compression
S. Saito, Koji Igarashi, M. Kishi, Masahiro Tsuchiya
International Topical Workshop on Contemporary Photonic Technologies (CPT2002) Vol. E-7 2002/06 Research paper (international conference proceedings)
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Broad-band and extremely flat super-continuum generation via optical parametric gain extended spectrally by fourth-order dispersion in anomalous-dispersion-flattened fibers
Koji Igarashi, Satoshi Saito, Masato Kishi, Masahiro Tsuchiya
IEEE Journal on Selected Topics in Quantum Electronics Vol. 8 No. 3 p. 521-526 2002/05 Research paper (scientific journal)
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Sub-100 fs higher order soliton compression in dispersion-flattened fibers
Masahiro Tsuchiya, K. Igarashi, S. Saito, M. Kishi
IEICE Transactions on Electronics Vol. E85-C No. 1 p. 141-149 2002/01 Research paper (scientific journal)
Publisher: The Institute of Electronics, Information and Communication Engineers
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Higher-order soliton compression of optical pulse from 5 ps to 20 fs by a 15.1-m-long single-stage step-like dispersion profiled fiber
Koji Igarashi, Masato Kishi, Masahiro Tsuchiya
Jpn. J. Appl. Phys. Vol. 40 No. 1 p. 6426-6429 2001/11 Research paper (scientific journal)
Publisher: The Japan Society of Applied Physics
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Sub-100 fs SDPF optical soliton compressor for diode laser pulses
M. Tsuchiya, K. Igarashi, R. Yatsu, K. Taira, K. Y. Koay, M. Kishi
Optical and Quantum Electronics Vol. 33 No. 7-10 p. 751-766 2001/07 Research paper (scientific journal)
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Stimulated Raman scattering effect on sub-50 fs soliton compression
Koji Igarashi, S. Saito, M. Kishi, Masahiro Tsuchiya
International Topical Workshop on Contemporary Photnic Technologies (CPT2001) Vol. P-02 2001/06 Research paper (international conference proceedings)
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All-optical switching module suitable for noise-suppressed detection of pulse position modulated codes
Takeshi Kamiya, Y. Komai, K. Kodate, R. Hainberger, Koji Igarashi, Masahiro Tsuchiya
Conference on Lasers and Electro-Optics (CLEO’01) Vol. CWB2 2001/05 Research paper (international conference proceedings)
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21fs higher-order soliton compression of semiconductor laser pulses by a step-like dispersion profiled fiber
Koji Igarashi, M. Kishi, Masahiro Tsuchiya
Fifth Optoelectronics and Communications Conference (OECC2000) Vol. 14D2-4 2000/07 Research paper (scientific journal)
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20 fs SDPF optical soliton compressor
Koji Igarashi, M. Kishi, Masahiro Tsuchiya
International Workshop on Femtosecond Technology (FST2000) Vol. TA-5 2000/06 Research paper (international conference proceedings)
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Proposal and simulateerformance of 1.55-um passive non-degenerate four-wave mixing devices employing coupled triple cavity structures
Koji Igarashi, T. Akiyama, Masahiro Tsuchiya
International Topical Workshop on Contemporary Photonic Technologies (CPT1999) Vol. Wep-9 1999/01 Research paper (international conference proceedings)
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Wavelength Conversion (~14nm) of 1-Gbit/s Signal by a Low-Temperature Grown Asymmetric Fabry-Perot All-Optical Device
T. Akiyama, Masahiro Tsuchiya, Koji Igarashi, Takeshi Kamiya
Conference on Lasers and Electro-Optics (CLEO’98) Vol. CThZ3 1998/05 Research paper (international conference proceedings)
