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. 14, 1995
Filed:
Feb. 28, 1995
Mizuyuki Ushirozawa, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A control circuit for reducing the output of an optical amplifier when reflected light associated with the output of the amplifier temporarily increases. An erbium-added optical fiber amplifies an input optical signal. Two optical detectors respectively detect the amplified optical signal and the reflected light. When a reflected light monitor signal does not exceed the level of a threshold signal, an output control circuit controls the intensity of an exciting light source in accordance with the an output light monitor signal. However, when the former exceeds the latter, the output control circuit reduces the output power of the optical signal. At this instant, the threshold level is lowered. As soon as the reflected light monitor signal becomes lower than the lowered threshold, an inverting amplifier causes the monitor signal to be restored to the original level.