Quantum dot two-mode laser at 1.55 μm-band for 90GHz radio over fiber applications. - Kouichi Akahane; Naokatsu Yamamoto; Atsushi Kanno; Toshimasa Umezawa; Tetsuya Kawanishi (ECOC, 2014)

Electro-optic devices for imaging systems using radio-over-fibre. - Tetsuya Kawanishi; Naokatsu Yamamoto; Toshimasa Umezawa; Kouichi Akahane; Atsushi Kanno; Pham Tien Dat (ICTON, 2014)

Bias free operational 107-Gbaud ultra-fast photodetector. - Toshimasa Umezawa; Kouichi Akahane; Naokatsu Yamamoto; Atsushi Kanno; Tetsuya Kawanishi (ECOC, 2015)

Zero-bias operational ultra-broadband UTC-PD above 110 GHz for high symbol rate PD-array in high-density photonic integration. - Toshimasa Umezawa; Kouichi Akahane; Naokatsu Yamamoto; Atsushi Kanno; Keizo Inagaki; Tetsuya Kawanishi (OFC, 2015)

Monolithically integrated quantum-dot optical modulator with semiconductor optical amplifier for 1.3µm waveband error-free 10-km-long transmission. - Naokatsu Yamamoto; Kouichi Akahane; Toshimasa Umezawa; Tetsuya Kawanishi (OFC, 2015)

A 1.55-µm Waveband Optical Absorption Characterization of an Electro-Absorption Device with a Highly Stacked InAs/InGaAlAs Quantum Dot Structure. - Naokatsu Yamamoto; Kouichi Akahane; Toshimasa Umezawa; Tetsuya Kawanishi (IEICE Trans. Electron., 2015)

31-GHz single-carrier, 44.6-Gbps photonic wireless transmission using a wide-bandwidth high power photodetector and a pre-distortion technique. - Toshimasa Umezawa; Kunihisa Jitsuno; Nobuhiko Shibagaki; Atsushi Kanno; Kouichi Akahane; A. Mstsumoto; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2016)

Spatial Coherent Matched Detection Using High-Speed Two Dimensional Photo-Diode Array for Full-Channel Demultiplexing and Demodulation of Mode-Division-Multiplexed Signals. - Takahide Sakamoto; Toshimasa Umezawa; Guo-Wei Lu; Kouichi Akahane; Atsushi Matsumoto; Atsushi Kanno; Naokatsu Yamamoto; Tetsuya Kawanishi (ECOC, 2017)

Dense SDM 32-Pixel 2-D Photodetector Array. - Toshimasa Umezawa; Tadashige Sakamoto; Atsushi Kanno; Ken Kusakata; Kouichi Akahane; Atsushi Matsumoto; Naokatsu Yamamoto; Tetsuya Kawanishi (ECOC, 2017)

100 GHz optical-to-radio converter module and its application in radio and power over fiber transmission through multi-core fiber. - Toshimasa Umezawa; Pham Tien Dat; Eiichi Hase; Kenichi Kashima; Atsushi Kanno; Kouichi Akahane; Atsushi Matsumoto; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2017)

Advanced Photonic Technologies for Future Mobile Communications and Imaging. - Pham Tien Dat; Atsushi Kanno; Toshimasa Umezawa (SoICT, 2017)

400-Gbps Space Division Multiplexing Optical Wireless Communication Using Two-Dimensional Photodetector Array. - Toshimasa Umezawa; Takahide Sakamoto; Atsushi Kanno; Shinya Nakajima; Atsushi Matsumoto; Naokatsu Yamamoto; Tetsuya Kawanishi (ECOC, 2018)

High-Speed and Handover-Free Communications for High-Speed Trains Using Switched WDM Fiber-Wireless System. - Pham Tien Dat; Atsushi Kanno; Keizo Inagaki; Toshimasa Umezawa; François Rottenberg; Jérôme Louveaux; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2018)

High-speed Two-dimensional Photodetector Array for 4-WDM 25-Gbaud FSO Communication. - Toshimasa Umezawa; Takahide Sakamoto; Atsushi Kanno; Kouichi Akahane; Atsushi Matsumoto; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2018)

Hybrid Optical Wireless-mmWave: Ultra High-Speed Indoor Communications for Beyond 5G. - Pham Tien Dat; Atsushi Kanno; Keizo Inagaki; Toshimasa Umezawa; Naokatsu Yamamoto; Tetsuya Kawanishi (INFOCOM Workshops, 2019)

Field Trial of 1.5-Gbps 97-GHz Train Communication System Based on Linear Cell Radio Over Fiber Network for 240-km/h High-Speed Train. - Atsushi Kanno; Pham Tien Dat; Toshimasa Umezawa; Naokatsu Yamamoto; Tetsuya Kawanishi; Nagateru Iwasawa; Nariya Iwaki; Kazuki Nakamura; Kunihiro Kawasaki; Naoki Kanada; Naruto Yonemoto; Yosuke Sato; et al. (OFC, 2019)

1-λ, 16-Parallel Lanes, 50-Gbaud On-Off Keying Multi-Core Fiber Communication Directly Coupled to High Speed 2D-Photodetector Array. - Toshimasa Umezawa; Atsushi Matsumoto; Atsushi Kanno; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2019)

Coherent Detection Only by 2-D Photodetector Array: A Discreteness-Aware Phase Retrieval Approach. - Yuki Yoshida; Toshimasa Umezawa; Atsushi Kanno; Naokatsu Yamamoto (OFC, 2019)

Characterization of 2D high-speed photodetector array device for SDM fiber communication applications. - Ken Kusakata; S. Takamizawa; Toshimasa Umezawa; Naokatsu Yamamoto; Tetsuya Kawanishi (OECC/PSC, 2019)

30 GHz Radio over FSO System using High Speed 2D-PDA and Its Optical Path Switching Performance. - Toshimasa Umezawa; Pham Tien Dat; Atsushi Kanno; Kunihisa Jitsuno; Naokatsu Yamamoto; Tetsuya Kawanishi (ECOC, 2020)

Phase-Retrieving Coherent Reception and its Sample Complexity. - Yuki Yoshida; Toshimasa Umezawa; Atsushi Kanno; Naokatsu Yamamoto (ECOC, 2020)

High Speed 2D-PDA FSO Receiver for High Optical Alignment Robustness with Space Diversity. - Toshimasa Umezawa; Yuki Yoshida; Atsushi Kanno; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2020)

On the Sample Complexity of Phase-Retrieval Receiver Based on 2-D Arrayed Photodetectors. - Yuki Yoshida; Toshimasa Umezawa; Atsushi Kanno; Keizo Inagaki; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2020)

Submillimeter Large High-speed Photodetector for High Optical Alignment Robustness Optical Wireless Communications. - Toshimasa Umezawa; Shinya Nakajima; Atsushi Kanno; Naokatsu Yamamoto (ECOC, 2021)

240-Gbps SDM-FSO communication using 4-bundle fiber and 2D photodetector array. - Toshimasa Umezawa; Kunio Jitsuno; Naokatsu Yamamoto; Tetsuya Kawanishi (OFC, 2021)

400-pixel high-speed photodetector for high optical alignment robustness FSO receiver. - Toshimasa Umezawa; Atsushi Matsumoto; Kouichi Akahane; Atsushi Kanno; Naokatsu Yamamoto (OFC, 2022)

High-Efficient Pixel Layout Arrangement in High-Speed 2-D Photodetector Array. - Siyang Duan; Toshimasa Umezawa; Atsushi Kanno; Tetsuya Kawanishi (OECC/PSC, 2022)

High-Speed Beam Steering LN Optical Phased Array Module using Comb-Electrode. - Hayato Takemura; Haruto Shinya; Yuya Yamaguchi; Toshimasa Umezawa; Atsushi Kanno; Tetsuya Kawanishi (OECC/PSC, 2022)

50 GHz High Photocurrent PIN-PD and Its Thermal Effect. - Yaofeng Yi; Toshimasa Umezawa; Atsushi Kanno; Tetsuya Kawanishi (OECC/PSC, 2022)

Self-Coherent Transmission Using Metasurface-based Stokes-Vector Receiver. - Go Soma; Yoshiro Nomoto; Toshimasa Umezawa; Yuki Yoshida; Yoshiaki Nakano; Takuo Tanemura (OFC, 2023)

100-Gbps 2-SDM 2-WDM FSO beam direct detection using resonant cavity 4x4 photodetector array. - Toshimasa Umezawa; Atsushi Matsumoto; Kouichi Akahane; Atsushi Kanno; Naokatsu Yamamoto (OFC, 2023)

Low Threshold and 10kHz-Class Narrow Linewidth 1.55 µm-Band Quantum Dot Laser Diode on InP(311)B Substrate. - Atsushi Matsumoto; Ryota Yabuki; Shinya Nakajima; Toshimasa Umezawa; Siim Heinsalu; Yuichi Matsushima; Koichi Akahane; Naokatsu Yamamoto; Katsuyuki Utaka (OFC, 2024)

DC-226 GHz well-impedance-matched high-speed photoreceiver for multi-band signal detection. - Toshimasa Umezawa; Pham Tien Dat; Yuki Yoshida; Shinya Nakajima; Atsushi Matsumoto; Kouichi Akahane; Atsushi Kanno; Naokatsu Yamamoto (OFC, 2024)

Demonstration of Robust Mobile Free Space Optical System using High-speed Beam Tracking and 2D-PDA-based Spatial-Diversity Reception. - Zu-Kai Weng; Yuki Yoshida; Toshimasa Umezawa; Abdelmoula Bekkali; Michikazu Hattori; Atsushi Matsumoto; Atsushi Kanno; Naokatsu Yamamoto; Tetsuya Kawanishi; Kouichi Akahane (OFC, 2024)

40-Gbit/s Mobile FSO with High-speed Beam Stabilizer and 2D-PDA-based Diversity Receiver for Support Robots. - Zu-Kai Weng; Yuki Yoshida; Toshimasa Umezawa; Abdelmoula Bekkali; Michikazu Hattori; Atsushi Matsumoto; Atsushi Kanno; Naokatsu Yamamoto; Tetsuya Kawanishi; Kouichi Akahane (OFC, 2024)

High-Responsivity Unitraveling Carrier-Type Photodetector Using Avalanche InAlAs as a Collector at a High-Frequency Range. - Yaofeng Yi; Toshimasa Umezawa; Kouichi Akahane; Tetsuya Kawanishi (IEEE Access, 2024)

Thermal Study for High-Photocurrent Photodetector in Non-Saturation Region Using Thin Substrate, Thin Absorber, and Flip- Chip Bonding Process. - Yaofeng Yi; Toshimasa Umezawa; Kouichi Akahane; Tetsuya Kawanishi (IEEE Access, 2024)

16 A/W, DC-200 GHz Ultra-Broadband Photoreceiver Module for High Baud Rate Small Signal Detection. - Toshimasa Umezawa; S. Nakajima; A. Matsumoto; Koichi Akahane; Atsushi Kanno; N. Yamamoto (OFC, 2025)