1
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 ...


2
Mitsuharu Noda, Setsuo Misaizu, Motoyoshi Sekiya, Yasunori Nagakubo: Optical transmitter, optical communication system and optical communication method. Fujitsu, Staas & Halsey, May 4, 1999: US05900959 (30 worldwide citation)

An optical transmitter comprises a first unit for generating an optical signal having a bandwidth given by a main signal, a second unit modulating the optical signal according to a control signal to extend the bandwidth of the optical signal, a third unit extracting backward light including SBS(stim ...


3
Mitsuharu Noda, Motoyoshi Sekiya, Setsuo Misaizu, Tetsuya Kiyonaga, Nobuaki Sato, Yasunori Nagakubo: Laser diode protecting circuit and laser driving current control circuit. Fujitsu, Staas & Halsey, May 8, 2001: US06229833 (26 worldwide citation)

Disclosed is a laser diode protecting circuit adapted to prevent a laser diode from producing an excessive emission when the laser diode is driven at low temperature, thereby assuring that the laser diode will not be damaged or degraded in terms of its characteristic. When the laser diode is started ...


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
Yoko Tahara, Yasunori Nagakubo: Optical Transmitter. Fujitsu, August 20, 1996: US05548435 (22 worldwide citation)

An optical transmitter for optimizing the duty ratio of a high-speed optical transmission signal has an output unit for providing an optical output signal according to an electric signal, a monitor circuit for providing an output representative signal related to the output of the output unit, a driv ...


6
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 ...


7
Hisaya Sakamoto, Takashi Tsuda, Yasunori Nagakubo: Discrimination circuit capable of automatically optimizing discrimination level and discrimination phase. Fujitsu, Helfgott & Karas PC, April 7, 1998: US05736875 (12 worldwide citation)

In controlling a discrimination level V.sub.1, V.sub.1 is controlled so that discrimination results based on discrimination levels V.sub.1 +.DELTA.V and V.sub.1 -.DELTA.V each become equal to the discrimination result based on the discrimination level V.sub.1. If the discrimination result based on V ...


8
Keisuke Imai, Yasunori Nagakubo: Optical transmitter and optical communication system. Fujitsu, Staas & Halsey, October 26, 1999: US05973812 (8 worldwide citation)

An optical transmitter and an optical communication system, each for providing a good transmission characteristic of a main signal and allowing suppression of SBS (stimulated Brillouin scattering). The optical transmitter comprises a light source for outputting a carrier beam, an optical modulator f ...


9
Akimitsu Miyazaki, Sadao Ibukuro, Yasunori Nagakubo: Optical transmitter, terminal-station apparatus having the optical transmitter, and optical communication system. Fujitsu, Staas & Halsey, March 21, 2000: US06040931 (8 worldwide citation)

An optical transmitter, a terminal-station apparatus having the optical transmitter, and an optical communication system employing the terminal-station apparatus. The optical transmitter comprises: a light-source unit for generating an optical signal; a monitor unit for monitoring a parameter depend ...


10
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, October 19, 1999: US05966938 (5 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 ...