Takashi Kotanigawa
Nippon Telegraph and Telephone
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Publication
Featured researches published by Takashi Kotanigawa.
optical fiber communication conference | 2007
Tomoyoshi Kataoka; Shinji Matsuoka; Toshiya Matsuda; Hideki Maeda; Norio Sakaida; Tsutomu Kubo; Takashi Kotanigawa; Takeshi Kawasaki
Using a commercially-ready 40-lambda DWDM system, RZ-DQPSK is confirmed to offer excellent DGD tolerance, up to 25 ps, through high PMD installed DSFs.
optical fiber communication conference | 2012
Shuto Yamamoto; Testuro Inui; Hiroto Kawakami; Shogo Yamanaka; Takeshi Kawai; Takashi Ono; Kunihiko Mori; Masahiro Suzuki; Ayako Iwaki; Tomoyoshi Kataoka; Mitsunori Fukutoku; Tadao Nakagawa; Toshikazu Sakano; Masahito Tomizawa; Yutaka Miyamoto; Senichi Suzuki; Koichi Murata; Takashi Kotanigawa; Akio Maeda
We demonstrate hybrid 40-Gb/s and 100-Gb/s PDM-QPSK DWDM transmission using real-time DSP in 580-km DSF-installed field testbed. The nonlinear crosstalk penalty due to the hybrid transmission of less than 0.5 dB is confirmed.
optical fiber communication conference | 2016
Hideki Maeda; Takashi Kotanigawa; Kohei Saito; Masahiro Yokota; Shuto Yamamoto; Fukutaro Hamaoka; Mitsuteru Yoshida; Masahiro Suzuki; Takeshi Seki
We achieve double the performance in 400-Gbps optical transmission employing advanced digital coherent technologies based on field trials. Additionally, we show stable transmission of 400-Gbps channels that does not affect the existing 100-Gbps channels.
european conference on optical communication | 2006
Toshiya Matsuda; Takeshi Kawasaki; Soichiroh Usui; Tsutomu Kubo; Takashi Kotanigawa; Shinji Matsuoka
43Gb/s Pre-chirped RZ-DQPSK WDM signal is successfully transmitted over 500-km with 12 OADM nodes. Pre-chirping suppresses the nonlinear penalty of WDM signals even though each has a level of different accumulated dispersion.
optical fiber communication conference | 2009
Toshiya Matsuda; Takeshi Kawasaki; Takashi Kotanigawa; Akira Naka; Kazuhiro Oda
We use long-term SOP measurements to assess the characteristic of SOP change in aerial fiber. We demonstrate field transmission of 43-Gbit/s RZ-DQPSK signals in aerial fiber with rapidly changing SOP; the results confirm stable transmission.
opto electronics and communications conference | 2017
Kohei Saito; Takashi Kotanigawa; Hideki Maeda
We analytically evaluate the transmission performance through 480-km WDM transmission of 256-Gb/s high baud rate single carrier signal and multicarrier signal with different number of subcarriers employing MIMO-based crosstalk compensation. We verify the effectiveness of multi-carrier transmission system employing MIMO-based crosstalk compensation achieves Q improvement at the sub-carrier spacing corresponds to approximately 88 % of the signal baud rate with two-sub-carrier PDM-QPSK signals.
european conference on optical communication | 2015
Kohei Saito; Masahiro Yokota; Fukutaro Hamaoka; Shuto Yamamoto; Takashi Kotanigawa; Hideki Maeda; Akira Naka
Hitless optical path switching using maximum ratio combining in route diversity transmission is successfully achieved under the condition of a field environment even if there are large polarization mode dispersion and fibre nonlinearities.
optical fiber communication conference | 2006
Takashi Kotanigawa; Hiroji Masuda; Toshiya Matsuda; Shinji Matsuoka
OSNR enhancement by using a novel pump-wave length detuning scheme for forward-pumped distributed Raman amplification in a 40 Gb/s-based L-band WDM in-line amplifier transmission system is experimentally verified for the first time.
optical fiber communication conference | 2004
Takashi Kotanigawa; Toshiya Matsuda; Akira Naka
Optical Amplifiers and Their Applications/Integrated Photonics Research (2004), paper OTuC3 | 2004
Toshiya Matsuda; Takashi Kotanigawa; Akira Naka
