1
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 ...


2
Norifumi Shukunami, Shinya Inagaki: Doped optical fiber having core and clad structure for increasing the amplification band of an optical amplifier using the optical fiber. Fujitsu, Staas & Halsey, July 7, 1998: US05778129 (27 worldwide citation)

An optical fiber having a core for propagating light, where the core includes first, second and third regions. The first, second and third regions are concentrically arranged with the second region around the first region and the third region around the second region. The third region includes a dop ...


3
Shinya Inagaki, Norifumi Shukunami, Susumu Kinoshita, Hiroyuki Itou, Taiki Kobayashi: Gain and signal level adjustments of cascaded optical amplifiers. Fujitsu, Staas & Halsey, August 5, 2003: US06603596 (23 worldwide citation)

An optical amplification device which includes first and second optical amplifiers, and a controller. The first optical amplifier receives a light and amplifies the received light. The second optical amplifier receives the light amplified by the first optical amplifier, and amplifies the received li ...


4
Norifumi Shukunami, Susumu Kinoshita, Toshio Hashi: Method and apparatus using four wave mixing for optical wavelength conversion. Fujitsu, Staas & Halsey, March 4, 2003: US06529314 (23 worldwide citation)

Method and apparatus using four wave mixing (FWM) for wavelength conversion. An optical waveguide doped with a rare earth element is pumped so that an input optical signal is amplified as the input optical signal travels through the optical waveguide. The optical waveguide is provided with at least ...


5
Shinya Inagaki, Kenji Tagawa, Norifumi Shukunami, Nobuhiro Fukushima: Method and apparatus for controlling optical amplifier used for optically amplifying wavelength-division multiplexed signal. Fujitsu, Staas & Halsey, April 28, 1998: US05745283 (16 worldwide citation)

A method and apparatus for controlling gain differences between optical signals, and hence an output of each individual optical signal, in an optical amplifier including a rare-earth-doped fiber for optically amplifying a wavelength-division multiplexed signal. Pumping light is injected into an erbi ...


6
Hiroaki Tomofuji, Takuji Maeda, Norifumi Shukunami, Tatsuya Tsuzuki, Yuichi Suzuki: Optical amplifier amplifying wavelength multiplexed light, and wavelength multiplexed light communications system. Fujitsu, Staas & Halsey, June 7, 2005: US06903324 (11 worldwide citation)

Wavelength multiplexed light is amplified by first and second EDFs. Gains of the first and the second EDFs are respectively held to be predetermined values by first and second AGC circuits. Between the first and the second EDFs, a variable attenuator is arranged. A loss in the variable attenuator is ...


7
Shinya Inagaki, Norifumi Shukunami, Susumu Kinoshita, Hiroyuki Itou, Taiki Kobayashi: Gain and signal level adjustments of cascaded optical amplifiers. Fujitsu, Staas & Halsey, June 13, 2006: US07061666 (10 worldwide citation)

An optical amplification device which includes first and second optical amplifiers, and a controller. The first optical amplifier receives a light and amplifies the received light. The second optical amplifier receives the light amplified by the first optical amplifier, and amplifies the received li ...


8
Norifumi Shukunami, Shinya Inagaki, Miki Takeda: Optical amplifying fiber and forming method for fiber grating. Fujitsu, Staas & Halsey, October 17, 2000: US06134046 (6 worldwide citation)

An optical amplifying fiber including a core doped with a rare earth element and having a first refractive index, a cladding surrounding the core and having a second refractive index smaller than the first refractive index, and a fiber grating formed in the core for transmitting signal light having ...


9
Norihisa Naganuma, Norifumi Shukunami: Optical amplifier and fiber module for optical amplification. Fujitsu, Staas & Halsey, October 30, 2001: US06310717 (6 worldwide citation)

Disclosed herein is an optical amplifier reduced in gain deviation. The optical amplifier includes a nonsilica fiber doped with a rare earth, and a fiber holder in which the nonsilica fiber is inserted and fixed. The fiber holder is optically arranged so that signal light to be amplified propagates ...


10
Shinya Inagaki, Norifumi Shukunami: Optical amplifier for collectively amplifying optical signals having a plurality of multiplexed wavelengths. Fujitsu, Staas & Halsey, January 19, 1999: US05861973 (4 worldwide citation)

Disclosed is an optical amplifier for collectively amplifying optical signals having multiplexed wavelengths. The optical amplifier enables a gain control in a range as wide as 1 dBm or larger, and employs a fiber that is doped with a rare-earth metal, such as erbium. The erbium-doped fiber in cross ...