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Dive into the research topics where Yuichi Kawahata is active.

Publication


Featured researches published by Yuichi Kawahata.


Journal of Lightwave Technology | 2002

40-Gb/s WDM transmission with virtually imaged phased array (VIPA) variable dispersion compensators

Hiroki Ooi; Kentaro Nakamura; Yuichi Akiyama; Tomoo Takahara; Takafumi Terahara; Yuichi Kawahata; Hideki Isono; George Ishikawa

We have demonstrated variable dispersion compensation by using a virtually imaged phased array (VIPA) to overcome the small dispersion tolerance in 40-Gb/s dense wavelength-division multiplexing (WDM) transmission systems. By utilizing the periodical characteristics of VIPA compensators, we performed simultaneous dispersion compensation in a 1.28-Tb/s (40-Gb/s/spl times/32 ch; C band) short-haul transmission and confirmed that only two VIPA compensators and one fixed dispersion-compensating fiber are required for a large transmission range of 80 km. This performance can greatly reduce the cost, size, and number of compensator menus in a 40-Gb/s WDM short-haul transmission system. In addition, we achieved 3.5-Tb/s (43-Gb/s/spl times/88 ch; C and L bands) transmission over a 600-km nonzero dispersion-shifted fiber by using VIPA compensators. Although channel-by-channel dispersion compensation is required due to the larger residual dispersion slope in long-haul transmission, the periodical characteristics of the VIPA compensators offer the advantage of considerably reducing the number of different modules required to cover the whole C (or L) band. An adequate optical signal-to-noise ratio, which was the same for all channels, was-obtained by using distributed Raman amplification, a gain equalizer, and a preemphasis technique. We achieved a Q-factor of more than 11.8 dB; (BER<10/sup -17/ with forward-error correction) for all 88 channels.


optical fiber communication conference | 2002

3.5-Tbit/s (43-Gbit/s /spl times/ 88 ch) transmission over 600-km NZDSF with VIPA variable dispersion compensators

Hiroki Ooi; Kentaro Nakamura; Yuichi Akiyama; T. Takahara; Junichi Kumasako; Jens C. Rasmussen; T. Terahara; Yuichi Kawahata; Hideki Isono; George Fujitsu Limited Ishikawa; N. Yamaguchi

Summary form only given. We performed 3.5-Tbit/s (43-Gbit/s /spl times/ 88 ch) 600 km transmission in the C- and L-bands by using virtually imaged phased array (VIPA) variable dispersion compensators. An adequate OSNR, which was the same for all the channels, was obtained by using distributed Raman amplification (DRA), a gain equalizer (GEQ), and a pre-emphasis technique. VIPA variable dispersion compensators can thus effectively overcome the small dispersion tolerance and temporal dispersion changes of dense WDM terabit systems. We achieved a Q-factor of more than 11.8 dB (BER < 10/sup -17/ with FEC) for all 88 channels.


Archive | 2001

Apparatus for variable wavelength dispersion and wavelength dispersion slope

Nobuaki Mitamura; Yuichi Kawahata


Archive | 2005

Transmission characteristics evaluation system and pseudo transmission path apparatus thereof

Yuichi Kawahata


Archive | 2002

Device using a virtually-imaged phased array (VIPA) with an improved transmission wave characteristic of output light

Yasuhiro Yamauchi; Yuichi Kawahata; Nobuaki Mitamura; Hirohiko Sonoda


Archive | 2004

Control method of wavelength dispersion compensator, and wavelength dispersion compensator

Yuichi Kawahata


Archive | 2004

Optical component provided with demultiplexing function and wavelength dispersion compensator

Yuichi Kawahata


Archive | 2002

Optical apparatus and device

Nobuaki Mitamura; Hirotomo Izumi; Yuichi Kawahata


Archive | 2004

Optical transmission apparatus, method for controlling optical transmission system, and optical relay node equipped with wavelength control function

Motoyoshi Sekiya; Yuichi Kawahata


Archive | 2003

Dispersion compensator with flattened transmission band

Yuichi Kawahata; Nobuaki Mitamura

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