1
Takashi Tsuda, Kazuo Yamane, Makoto Murakami, Tooru Shima, Tooru Matsumoto, Hiroyuki Iwaki, Kazuto Imai: Method of activating optical communication system, channel increasing/decreasing method, and computer-readable recording medium. Fujitsu, January 4, 2005: US06839160 (98 worldwide citation)

The invention relates to a method of activating an optical communication system comprising a plurality of optical amplifiers having an optical amplifier, between optical transmission lines in which wavelength-division multiplex optical signals are transmitted. The method comprises steps of: generati ...


2
Tsukasa Takahashi, Hiroyuki Itou, Yuji Tamura, Michikazu Shima, Kazuo Yamane, Yumiko Kawasaki, Keisuke Imai, Yoshinori Ohkuma, Kazuhiro Suzuki, Yasunori Nagakubo, Takashi Tsuda, Yuji Miyaki: Optical amplifier and optical transmission apparatus. Fujitsu, Helfgott & Karas P C, October 21, 1997: US05680246 (31 worldwide citation)

The optical amplifier includes a doped fiber doped with a rare earth element, a pumping light source, means for introducing signal light and pumping light into the doped fiber, detection means for detecting whether or not amplified signal light is included in light outputted from the doped fiber, an ...


3
Takashi Tsuda, Hiroshi Nishimoto, Kazuo Yamane, Yumiko Kawasaki, Satoru Okano: Optical amplifier and optical transmission system including the optical amplifier. Fujitsu, Staas & Halsey, March 14, 2000: US06038063 (30 worldwide citation)

An optical amplifier relates to WDM (wavelength division multiplexing). The optical amplifier includes an optical amplifying unit, an ALC (automatic output level control) circuit for controlling the unit based on the output level thereof, and AGC (automatic gain control) circuit for controlling the ...


4
Yasunori Nagakubo, Sadao Ibukuro, Akihiko Hayashi, Takashi Tsuda: Light transmitter having an automatic bias control circuit. Fujitsu, Helfgott & Karas P C, May 4, 1999: US05900621 (25 worldwide citation)

In a light transmitter comprises an automatic bias control circuit which automatically controls a bias for an external modulator, a part of a light output/input signal of the external modulator is branched to detect an electrical monitor signal and a gain control signal is generated in inverse propo ...


5
Yasunori Nagakubo, Takashi Tsuda, Tetsuo Ishizaka, Shunichi Sato, Saeko Yokoi, Manabu Komiyama, Toshio Ohya, Noriaki Mizuguchi: Peltier control circuit and a peltier device structure. Fujitsu, Armstrong Westerman Hattori McLeland & Naughton, May 14, 1996: US05515682 (20 worldwide citation)

A Peltier control circuit detects a temperature of a device combined with a Peltier device and controls a current flowing through the Peltier device so as to keep the temperature of the device at a predetermined value. The circuit has a temperature sensing section for detecting the temperature of a ...


6
Kazuo Yamane, Masakazu Mori, Takashi Tsuda, Yoshinori Ohkuma, Kazuhiro Suzuki: Semiconductor laser driving device. Fujitsu, Staas & Halsey, March 14, 1989: US04813048 (20 worldwide citation)

A semiconductor laser driving device using FET's as a positive element in a bias current supply circuit and a pulse current supply circuit, and having compensating circuits for compensating differences in the characteristics of the FET's and a laser diode used in the driving device. Also a pulse amp ...


7
Yumiko Kawasaki, Satoru Okano, Kazuo Yamane, Hiroshi Nishimoto, Takashi Tsuda: Optical amplifier and optical communication system having the optical amplifier. Fujitsu, Staas & Halsey, September 11, 2001: US06288836 (19 worldwide citation)

The present invention relates to an optical amplifier and an optical communication system applied to WDM (wavelength division multiplexing). The optical amplifier includes an optical amplifying medium to which WDM signal light obtained by wavelength division multiplexing a plurality of optical signa ...


8
Takashi Tsuda, Kazuo Yamane, Yumiko Kawasaki, Satoru Okano: Method for optical fiber communication, and terminal device and system for use in carrying out the method. Fujitsu, Staas & Halsey, May 18, 2004: US06738584 (16 worldwide citation)

The present invention relates to a method for optical fiber communication, and a terminal device and system for use in carrying out the method, and an object of the present invention is to compensate for chromatic dispersion and nonlinearity. A device for outputting an optical signal having a variab ...


9
Setsuo Misaizu, Sunao Itou, Takashi Tsuda: Optical transmitter and laser diode module for use in the optical transmitter. Fujitsu, Helfgott & Karas P C, July 8, 1997: US05646763 (14 worldwide citation)

An optical transmitter includes a laser diode module including a laser diode which outputs a light signal to a transmission line, a driving unit which drives the laser diode in accordance with an input signal indicative of data to be transmitted, and a coupling unit for connecting an output of the d ...


10
Shinya Inagaki, Hisashi Takamatsu, Kazuo Yamane, Takashi Tsuda: Apparatus and method of compensating for wavelength dispersion of optical transmission line. Fujitsu, Staas & Halsey, June 1, 2004: US06744958 (13 worldwide citation)

Both wavelength dispersion and a dispersion slope of a line fiber are simultaneously compensated for by combining two types of dispersion compensators having different characteristics.