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Dive into the research topics where Naoki Kuwata is active.

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Featured researches published by Naoki Kuwata.


international solid-state circuits conference | 2009

A Single-40 Gb/s Dual-20 Gb/s Serializer IC With SFI-5.2 Interface in 65 nm CMOS

Kouichi Kanda; Hirotaka Tamura; Takuji Yamamoto; Satoshi Matsubara; Masaya Kibune; Yoshiyasu Doi; Takayuki Shibasaki; Nestoras Tzartzanis; Anders Kristensson; Samir Parikh; Satoshi Ide; Yukito Tsunoda; Tetsuji Yamabana; Mariko Sugawara; Naoki Kuwata; Tadashi Ikeuchi; Junji Ogawa; Bill Walker

This paper presents a 40 Gb/s serializer IC in 65 nm bulk CMOS technology. The IC has an SFI5.2-compliant 10 Gb/s input interface and supports two different output modes, single 40 Gb/s for OC-768 VSR and dual 20 Gb/s for DQPSK. The IC is evaluated on a PCB and error-free operation is confirmed. The chip consumes 1.8 W for the 40 G mode, and 1.6 W for the 20 G mode from 1.2 V and 3.3 V power supplies.


Journal of Lightwave Technology | 1988

New method analyzing eye patterns and its application to high-speed optical transmission system

Hiroshl Nishimoto; Tadashi Fujimiso Okiyama; Naoki Kuwata; Yasunari Arai; Akira Miyauchi; Takashi Touge

An advanced method of analyzing eye patterns is proposed which plots the eye pattern as a function of the error rate. The method is applied to high-speed optical-transmission systems and its usefulness is confirmed. Degradation of eye opening due to noise and intersymbol interference is investigated quantitatively using the 10/sup -10/ BER eye. An automatic gain-control system is evaluated from a viewpoint of eye margin, and a gain control system having an improved eye margin performance is proposed. Low-probability abnormal phenomena, such as turn-on fluctuations and mode partitioning in directly modulated distributed feedback (DFB) lasers, are observed using this method. >


compound semiconductor integrated circuit symposium | 2010

A 3 Watt 39.8–44.6 Gb/s Dual-Mode SFI5.2 SerDes Chip Set in 65 nm CMOS

Nikola Nedovic; Anders Kristensson; Samir Parikh; Subodh M. Reddy; Scott McLeod; Nestoras Tzartzanis; Kouichi Kanda; Takuji Yamamoto; Satoshi Matsubara; Masaya Kibune; Yoshiyasu Doi; Satoshi Ide; Yukito Tsunoda; Tetsuji Yamabana; Takayuki Shibasaki; Yasumoto Tomita; Takayuki Hamada; Mariko Sugawara; Tadashi Ikeuchi; Naoki Kuwata; Hirotaka Tamura; Junji Ogawa; William W. Walker

A Dual-mode 2 ×21.5-22.3 Gb/s DQPSK or 1 × 39.8-44.6 Gb/s NRZ to 4 × 9.95-11.2 Gb/s SFI5.2-compliant two-chip SerDes for a family of 40 Gb/s optical transponders has been fabricated in 65 nm 12-metal CMOS. By demultiplexing to 16 × 2.5 Gb/s internally, all logic and testability functions could be implemented in standard-cell CMOS, resulting in total power consumption of 3 W, 75 % lower than commercial BiCMOS SFI5 40 Gb/s SerDes ICs. Chip area is 4 × 4 mm, and the ICs are flip-chip mounted into a quad flat-pack package.


european conference on optical communication | 2010

30-Gb/s VCSEL transmitter fabricated on flexible printed circuit substrate

Takatoshi Yagisawa; Takashi Shiraishi; Naoki Kuwata; Tadashi Ikeuchi

A VCSEL transmitter was fabricated on an flexible printed circuit substrate. The transmitter achieved clear eye opening with an extinction ratio of 4.6 dB and error-free operation at 30-Gb/s, demonstrating the applicability of the FPC for high-speed transmitter applications.


Archive | 2005

Optical transmitting apparatus, optical receiving apparatus, and optical communication system comprising them

Yuichi Akiyama; Takeshi Hoshida; Akira Miura; Yutaka Fujitsu Limited Kai; Hiroki Fujitsu Limited Ooi; Jens C. Rasmussen; Kentaro Nakamura; Naoki Kuwata; Yoshinori Nishizawa; Tomoo Takahara; Masahiro Yuki


Archive | 1998

Method and apparatus for optimizing dispersion in an optical fiber transmission line in accordance with an optical signal power level

George Ishikawa; Hiroki Ooi; Naoki Kuwata


Archive | 2006

Optical signal reception device and method of controlling optical signal reception

Toru Katagiri; Takeshi Hoshida; Tomoo Takahara; Kentaro Nakamura; Naoki Kuwata


Archive | 2005

DQPSK optical receiver circuit

Tadashi Ikeuchi; Naoki Kuwata


Archive | 2005

Optical signal reception device

Toru Katagiri; Takeshi Hoshida; Tomoo Takahara; Kentaro Nakamura; Naoki Kuwata


Archive | 1990

CONTROL SYSTEM FOR EXTERNAL MODULATOR

Naoki Kuwata; Hiroshi Nishimoto

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