An all DC-powered Josephson logic circuit. - Yuji Hatano; Hideyuki Nagaishi; Shinichiro Yano; Kouji Nakahara; Hiroji Yamada; Shinya Kominami; Mikio Hirano (IEEE J. Solid State Circuits, 1991)

High-Temperature and High-Speed Performances of InGaAlAs-MQW DFB Lasers for 10-Gb/s Datacom Applications. - Kouji Nakahara (IEICE Trans. Electron., 2005)

100-Gb/s Physical-Layer Architecture for Next-Generation Ethernet. - Hidehiro Toyoda; Shinji Nishimura; Michitaka Okuno; Kouji Fukuda; Kouji Nakahara; Hiroaki Nishi (IEICE Trans. Commun., 2006)

28-Gb/s directly modulated InGaAlAs ACPM DFB lasers with high mask margin of 22% at 55°C. - Kouji Nakahara; Yuki Wakayama; K. Hiruma; Takeshi Kitatani; Kazunori Shinoda; T. Fukamachi; Yasushi Sakuma; Shigehisa Tanaka (OFC/NFOEC, 2013)

56-Gb/s direct modulation in InGaAlAs BH-DFB lasers at 55°C. - Kouji Nakahara; Yuki Wakayama; Takeshi Kitatani; Takafumi Taniguchi; Toshihiko Fukamachi; Yasushi Sakuma; Shigehisa Tanaka (OFC, 2014)

Capability of high optical-feedback tolerance and non-hermetic-packaging for low-cost interconnections using lens-integrated surface-emitting laser. - Takanori Suzuki; Koichiro Adachi; Aki Takei; Yuki Wakayama; Akira Nakanishi; Kazuhiko Naoe; Kouji Nakahara; Shigehisa Tanaka; Kazuhisa Uomi (OFC, 2015)

A 50-Gb/s NRZ-modulated optical transmitter based on a DFB-LD and a 0.18-µm SiGe BiCMOS LD driver. - Takashi Takemoto; Yasunobu Matsuoka; Yoshikazu Sugiyama; Hidenori Yonezawa; Hiroki Yamashita; Koichiro Adachi; Takahiro Nakamura; Etsuko Nomoto; Kouji Nakahara; Hideo Arimoto; Kenichi Osada; Tatemi Ido (OFC, 2015)

A facet-free 1.3-µm surface-emitting DFB laser for a low-cost optical module. - Koichiro Adachi; Takanori Suzuki; Kouji Nakahara; Shigehisa Tanaka; Akira Nakanishi; Kazuhiko Naoe (IEICE Electron. Express, 2016)

Monolithically integrated 4 ch × 25.8 Gbps lens-integrated surface-emitting DFB laser array directly coupled to SMF. - Koichiro Adachi; Takanori Suzuki; Aki Takei; Kouji Nakahara; Shigehisa Tanaka; Akira Nakanishi; Kazuhiko Naoe (IEICE Electron. Express, 2016)

Superior BER Transmission of 106-Gb/s/lane Skewless PAM4 over 10 km by Utilizing 1.3-μm Directly Modulated InGaAlAs-MQW BH Lasers and Incoherent Multiplexing of Two NRZ Signals. - Kouji Nakahara; Riu Hirai; Takeshi Kitatani; Nobuhiko Kikuchi; Takayoshi Fukui; Kaoru Okamoto; Yasushi Sakuma; Kohichi Robert Tamura; Shigehisa Tanaka (OFC, 2018)

Analysis of TDECQ Dependence on Skew and Extinction Ratio with 106-Gb/s PAM-4 Modulation of Directly Modulated Submicron Ridge Localized Buried Heterostructure Lasers. - Kazuki Suga; Kouji Nakahara; Kaoru Okamoto; Shigenori Hayakawa; Masatoshi Arasawa; Tetsuya Nishida; Ryu Washino; Takeshi Kitatani; Masatoshi Mitaki; Hironori Sakamoto; Yasushi Sakuma; Shigehisa Tanaka (OFC, 2020)

112-Gb/s PAM-4 Uncooled Directly Modulated BH Lasers. - Kouji Nakahara; Kazuki Suga; Kaoru Okamoto; Shigenori Hayakawa; Masatoshi Arasawa; Tetsuya Nishida; Ryu Washino; Takeshi Kitatani; Masatoshi Mitaki; Hironori Sakamoto; Yasushi Sakuma; Shigehisa Tanaka (ECOC, 2021)

Over 100 mW Uncooled Operation of SOA-integrated 1.3-µm Highly Reliable CW-DFB Laser. - Shoko Yokokawa; Atsushi Nakamura; Shigetaka Hamada; Ryosuke Nakajima; Kaoru Okamoto; Masatoshi Arasawa; Kouji Nakahara; Shigehisa Tanaka (OFC, 2022)

CW-WDM MSA compatible 100-mW (up to 50°C), 400-GHz spacing highly-reliable CW-DFB 8-channel laser array. - Ryosuke Hatai; Kouji Nakahara; Atsushi Nakamura; Takayuki Nakajima; Yoshihiko Kobayashi; Takeo Kageyama; Shigehisa Tanaka (OFC, 2024)