The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 1998
Filed:
Feb. 26, 1996
Shu Yamamoto, Tokyo, JP;
Hidenori Taga, Tokyo, JP;
Noboru Edagawa, Tokyo, JP;
Shigeyuki Akiba, Tokyo, JP;
Kuniaki Motoshima, Tokyo, JP;
Katsumi Takano, Tokyo, JP;
Tadayoshi Kitayama, Tokyo, JP;
Kokusai Denshin Denwa Co., Ltd., Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
This invention provides an optical amplifier which has low noise characteristics for a wide range of input signal electric power. The optical amplifier has a plurality of cascaded optical amplifying units, a signal level detector, and a pump-source controller. The pump-source controller changes controlling objects from a pump-source corresponding to a first one of the optical amplifying units to a pump-source corresponding to a second one of the optical amplifying units according to a detection level of the signal level detector from a low level to a high level. When the detection level is outside of a control object range, the optical amplifier controls an output from the pump-source to stabilize. When the detection level is within the control object range, the optical amplifier controls an output from a pump-source of each of optical amplifying units according to the detection level.