1
Yasushi Sugaya, Miki Takeda, Susumu Kinoshita, Terumi Chikama: Multi-wavelength light amplifier. Fujitsu, Staas & Halsey, April 25, 2000: US06055092 (64 worldwide citation)

A multi-wavelength light amplifier includes a first-stage light amplifier which has a first light amplifying optical fiber amplifying a light input, a second-stage light amplifier which has a second light amplifying optical fiber amplifying a first light output from the first-stage light amplifier, ...


2
Yasushi Sugaya, Susumu Kinoshita, Hiroshi Onaka, Terumi Chikama: Optical amplifying apparatus. Fujitsu, Helfgott & Karas P C, April 7, 1998: US05737118 (55 worldwide citation)

A computer-controlled optical amplifying apparatus, which includes an optical amplifying unit including an optical amplifying medium and an optical amplifying control unit controlling the optical amplifying unit under the control of a computer. This optical amplifying control unit is constituted by ...


3
Yuichi Akiyama, George Ishikawa, Hiroki Ooi, Terumi Chikama: Optical transmitter and optical transmission system. Fujitsu, Staas & Halsey, December 9, 2003: US06661974 (43 worldwide citation)

An optical transmitter having a function which compensates for wavelength dispersion is provided with a plurality of light sources for outputting light having wavelengths that differ from one another. Before the optical transmission system begins operating, the wavelength of light output to an optic ...


4
Hiroshi Onaka, Hideyuki Miyata, Kazue Otsuka, Yutaka Kai, Tadao Nakazawa, Terumi Chikama: Optical transmission apparatus, optical transmission system, and optical terminal station. Fujitsu, Staas & Halsey, February 26, 2002: US06351323 (42 worldwide citation)

In an OADM system, an OADM device includes an AOTF. The AOTF can select an optional wavelength by changing the frequency of an RF signal to be applied. An optical signal having a specified wavelength can be dropped from a wavelength-multiplexed optical signal input from an input terminal, or a wavel ...


5
Takao Naito, Terumi Chikama, Shigeki Watanabe, Tetsuya Kiyonaga, Yoshihito Onoda, Hideo Kuwahara, Hiroshi Onaka, Hideyuki Miyata: Polarization diversity optical receiver for coherent optical communication. Fujitsu, Staas & Halsey, October 23, 1990: US04965858 (37 worldwide citation)

A polarized wave diversity optical receiver for coherent optical communication including: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for mixing signal light and the local oscillating light to obtain two polarized components; a detecting cir ...


6
Takao Naito, Terumi Chikama, Shigeki Watanabe, Tetsuya Kiyonaga, Yoshihito Onoda, Hideo Kuwahara: Receiver for coherent optical communication. Fujitsu, Staas & Halsey, May 19, 1992: US05115332 (34 worldwide citation)

A receiver for coherent optical communication in a phase diversity system. An optical hybrid circuit receives a signal beam and receives a local-oscillator beam which has a predetermined phase shift. The optical hybrid circuit branches each beam into pairs, each pair having one signal beam and one l ...


7
Kazue Okazaki, Hiroshi Onaka, Hideyuki Miyata, Yutaka Kai, Terumi Chikama: Optical cross connect unit, optical add-drop multiplexer, light source unit, and adding unit. Fujitsu, Staas & Halsey, September 4, 2001: US06285479 (33 worldwide citation)

The present invention relates to an optical cross connect unit comprising M wavelength separating sections for receiving multiplexed optical signals each having N kinds of wavelengths different from each other through M optical fibers, respectively, and for wavelength-separating each of the multiple ...


8
Yutaka Kai, Terumi Chikama: Optical transmission device for bi-directional optical communication. Fujitsu, Staas & Halsey, August 21, 2001: US06278536 (28 worldwide citation)

This invention discloses an optical transmission device used for bi-directional optical communications. The optical transmission device comprises a uni-directional optical signal processing unit for performing specified optical signal processing for optical signals transmitted in a single direction ...


9
Chihiro Ohshima, Susumu Kinoshita, Terumi Chikama: Optical amplifier for use in optical communications equipment. Fujitsu, Staas & Halsey, April 16, 2002: US06373623 (22 worldwide citation)

The output level of pumping light supplied from a pumping light source is varied using a variable attenuator, which is controlled by a variable attenuator driver circuit. By separating a portion containing the pumping light source from a portion containing an amplification medium, it becomes possibl ...


10
Takao Naito, Terumi Chikama, Shigeki Watanabe, Tetsuya Kiyonaga, Yoshihito Onoda: Heterodyne receiver for coherent optical communication. Fujitsu, Staas & Halsey, September 24, 1991: US05052051 (22 worldwide citation)

After mixing the signal light and the local oscillation light with a mixing circuit, two intersecting polarization components are divided by a polarization splitter and respective components are subjected to heterodyne detection by optical receivers. Thereafter, in an electric signal stage, the inte ...