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
Akira Miyauchi, Kazuo Yamane, Yumiko Kawasaki, Satoru Okano: Optical transmission system. Fujitsu, Staas & Halsey, March 2, 1999: US05877881 (56 worldwide citation)

A chirping parameter .alpha. in a transmitter is set to a positive value with respect to an SMF that has a positive dispersion value with respect to signal light. A dispersion compensator is provided not only at the receiving end but also at the transmitting end. This achieves a reduction in the num ...


3
Kazuo Yamane, Michikazu Shima, Yumiko Kawasaki, Kenji Tagawa, Shinya Inagaki, Norifumi Shukunami: Wavelength-division-multiplexing optical amplifier. Fujitsu, Helfgott & Karas P C, June 9, 1998: US05764404 (53 worldwide citation)

An optical amplifier amplifies a wavelength division-multiplexed optical input signal composed of optical signals having different wavelengths such that the output level of each of the optical signal is always optimized and such that the difference between the gains of the amplifier on the optical s ...


4
Kazuo Yamane, Naonobu Fujimoto, Takashi Kihara, Takeo Fukushima, Koichi Nishimura, Hatsumi Iino: Switching system of optical transmission lines for protecting from trouble. Fujitsu, Staas & Halsey, July 5, 1994: US05327275 (38 worldwide citation)

A system for optical communication between first and second optical terminal stations, containing a plurality of working optical transmission lines each for connecting between the first and second optical terminal stations, a protection optical transmission line. Each of the first and second optical ...


5
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 ...


6
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 ...


7
Hiroyuki Itou, Kazuo Yamane, Michikazu Shima: Multi-wavelength optical batch amplification apparatus. Fujitsu, Helfgott & Karas P C, February 9, 1999: US05870217 (25 worldwide citation)

The invention provides a multi-wavelength optical batch amplification apparatus wherein, upon batch amplification of a multi-wavelength input optical signal, the powers of optical signals on the input and output sides of an optical amplifier are monitored totally or individually to control the power ...


8
Takafumi Terahara, Takeshi Sakamoto, Hiroaki Tomofuji, Motoyoshi Sekiya, Makoto Murakami, Kazuo Yamane, Hiroshi Onaka: Method and apparatus for measuring optical signal-to-noise ratio, and pre-emphasis method and optical communication system each utilizing the method. Fujitsu, Staas & Halsey, November 25, 2003: US06654561 (24 worldwide citation)

In a method of measuring an optical signal-to-noise ratio according to the present invention, a partial optical signal-to-noise ratio is defined, the partial optical signal-to-noise ratio is calculated from a predetermined physical quantity, the sum of inverse numbers of the partial optical signal-t ...


9
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 ...


10
Kazuo Yamane: Communications system having optical transmission line switching system. Fujitsu, Armstrong Westerman Hattori McLeland & Naughton, July 18, 1995: US05434691 (19 worldwide citation)

A communications system includes a plurality of optical transmission lines in an active system and an optical transmission line in a protection system, and transmitter/receiver devices connected to respective ends of the optical transmission lines. The transmitter/receiver devices respectively inclu ...