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:
Nov. 16, 1999
Filed:
Mar. 11, 1998
Hiroyuki Itou, Sapporo, JP;
Tsukasa Takahashi, Sapporo, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical amplifier prevents generation of an optical surge when an input signal to the optical amplifier is interrupted. A synthesized signal of an input signal light and a pumping light is input to an optical amplifying medium. An input signal light interruption detecting circuit detects an interruption of the input signal light. A variable attenuator element is provided on a signal light input side of the optical amplifying medium so as to attenuate the input signal light. The variable attenuator element is controlled based on an output of the input signal light interruption detecting circuit so that a degree of attenuation of the variable attenuator element is increased when the input signal light is interrupted and the degree of attenuation is gradually decreased when the input signal light returns.