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
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
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 ...


4
Hiroyuki Itou, Michikazu Shima, Yoshihito Onoda, Yuji Tamura: Control apparatus for optical amplifier. Fujitsu, Helfgott & Karas P C, October 13, 1998: US05822112 (12 worldwide citation)

A control apparatus for an optical amplifier such as an erbium-doped optical-fiber (EDF) amplifier suppresses overshooting of ALC control at power on and at the time of input light restoration from an off condition, while ensuring quick starting. At power on and at the time of input light restoratio ...


5
Michikazu Shima, Hiroshi Nishimoto: Optical amplifying apparatus. Fujitsu, Staas & Halsey, April 25, 2000: US06055094 (11 worldwide citation)

The object of the present invention is to provide an optical amplifying apparatus for collectively amplifying wavelength-division multiplexed signal lights, which can perform amplification in response to input signal light, whose power level is within a wide input dynamic range, without saturating, ...


6
Yuji Tamura, Hiroyuki Itou, Tsukasa Takahashi, Michikazu Shima, Yumiko Kawasaki, Kazuo Yamane: Auxiliary-signal transmission system. Fujitsu, April 29, 1997: US05625481 (11 worldwide citation)

Spontaneous emission occurring in association with direct optical amplification using an erbium-doped optical fiber is modulated with an auxiliary signal, such as a supervisory signal, for transmission of the auxiliary signal. In a first aspect of the invention, the output of an optical amplifier is ...


7
Yuji Miyaki, Michikazu Shima: Drive circuit for electronic device. Fujitsu, February 18, 1997: US05604759 (10 worldwide citation)

A drive circuit drives an electronic device that converts electric power into light or heat energy. The drive circuit has a switch connected to the electronic device in series, and a control circuit for providing, in response to an input control signal, a pulse modulation signal for controlling the ...


8
Yuji Tamura, Hiroyuki Itou, Tsukasa Takahashi, Michikazu Shima, Yumiko Kawasaki, Kazuo Yamane: Auxiliary-signal transmission system. Fujitsu, Helfgott & Karas P C, November 24, 1998: US05841558 (3 worldwide citation)

Spontaneous emission occurring in association with direct optical amplification using an erbium-doped optical fiber is modulated with an auxiliary signal, such as a supervisory signal, for transmission of the auxiliary signal. In a first aspect of the invention, the output of an optical amplifier is ...


9
Yuji Tamura, Hiroyuki Itou, Tsukasa Takahashi, Michikazu Shima, Yumiko Kawasaki, Kazuo Yamane: Auxiliary-signal transmission system. Fujitsu, Helfgott & Karas P C, August 25, 1998: US05798857 (3 worldwide citation)

Spontaneous emission occurring in association with direct optical amplification using an erbium-doped optical fiber is modulated with an auxiliary signal, such as a supervisory signal, for transmission of the auxiliary signal. In a first aspect of the invention, the output of an optical amplifier is ...


10
Kazuo Yamane, Michikazu Shima, Yumiko Kawasaki, Kenji Tagawa, Shinya Inagaki, Norifumi Shukunami: Wavelength-division-multiplexing optical amplifier. Fujitsu, Helfgott & Karas P C, May 9, 2000: US06061173 (3 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 ...