Toshimasa Umezawa

According to our database, Toshimasa Umezawa authored at least 37 papers between 2014 and 2024.

Collaborative distances:

• Dijkstra number of four.
• Erdős number of four.

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

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

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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2024

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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2024

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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2023

Self-Coherent Transmission Using Metasurface-based Stokes-Vector Receiver.

Go Soma, Yoshiro Nomoto, Toshimasa Umezawa, Yuki Yoshida, Yoshiaki Nakano, Takuo Tanemura

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2023

2022

50 GHz High Photocurrent PIN-PD and Its Thermal Effect.

Yaofeng Yi, Toshimasa Umezawa, Atsushi Kanno, Tetsuya Kawanishi

Proceedings of the 2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (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

Proceedings of the 2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC), 2022

High-Efficient Pixel Layout Arrangement in High-Speed 2-D Photodetector Array.

Siyang Duan, Toshimasa Umezawa, Atsushi Kanno, Tetsuya Kawanishi

Proceedings of the 2022 27th OptoElectronics and Communications Conference (OECC) and 2022 International Conference on Photonics in Switching and Computing (PSC), 2022

400-pixel high-speed photodetector for high optical alignment robustness FSO receiver.

Toshimasa Umezawa, Atsushi Matsumoto, Kouichi Akahane, Atsushi Kanno, Naokatsu Yamamoto

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2022

2021

240-Gbps SDM-FSO communication using 4-bundle fiber and 2D photodetector array.

Toshimasa Umezawa, Kunio Jitsuno, Naokatsu Yamamoto, Tetsuya Kawanishi

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2021

Submillimeter Large High-speed Photodetector for High Optical Alignment Robustness Optical Wireless Communications.

Toshimasa Umezawa, Shinya Nakajima, Atsushi Kanno, Naokatsu Yamamoto

Proceedings of the European Conference on Optical Communication, 2021

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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2020

Phase-Retrieving Coherent Reception and its Sample Complexity.

Yuki Yoshida, Toshimasa Umezawa, Atsushi Kanno, Naokatsu Yamamoto

Proceedings of the European Conference on Optical Communications, 2020

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

Proceedings of the European Conference on Optical Communications, 2020

2019

Characterization of 2D high-speed photodetector array device for SDM fiber communication applications.

Ken Kusakata, S. Takamizawa, Toshimasa Umezawa, Naokatsu Yamamoto, Tetsuya Kawanishi

Proceedings of the 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC), 2019

Coherent Detection Only by 2-D Photodetector Array: A Discreteness-Aware Phase Retrieval Approach.

Yuki Yoshida, Toshimasa Umezawa, Atsushi Kanno, Naokatsu Yamamoto

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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, Masato Fujii, Katsuya Yanatori, Nobuhiko Shibagaki, Kenichi Kashima

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2019

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

Proceedings of the IEEE INFOCOM 2019, 2019

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

Proceedings of the Optical Fiber Communications Conference and Exposition, 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

Proceedings of the Optical Fiber Communications Conference and Exposition, 2018

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

Proceedings of the European Conference on Optical Communication, 2018

2017

Advanced Photonic Technologies for Future Mobile Communications and Imaging.

Pham Tien Dat, Atsushi Kanno, Toshimasa Umezawa

Proceedings of the Eighth International Symposium on Information and Communication Technology, 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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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

Proceedings of the European Conference on Optical Communication, 2017

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

Proceedings of the European Conference on Optical Communication, 2017

2016

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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2016

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

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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 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

Proceedings of the Optical Fiber Communications Conference and Exhibition, 2015

Bias free operational 107-Gbaud ultra-fast photodetector.

Toshimasa Umezawa, Kouichi Akahane, Naokatsu Yamamoto, Atsushi Kanno, Tetsuya Kawanishi

Proceedings of the European Conference on Optical Communication, 2015

2014

Electro-optic devices for imaging systems using radio-over-fibre.

Tetsuya Kawanishi, Naokatsu Yamamoto, Toshimasa Umezawa, Kouichi Akahane, Atsushi Kanno, Pham Tien Dat

Proceedings of the 16th International Conference on Transparent Optical Networks, 2014

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

Proceedings of the European Conference on Optical Communication, 2014