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:
Jul. 01, 1997
Filed:
Mar. 13, 1996
Tadayuki Iwano, Tokyo, JP;
NEC Corporation, , JP;
Abstract
In an optical amplifying device, an optical direct amplifier (11) amplifies input optical signals subjected to wavelength division multiplexing (WDM). A beam splitter (12) splits the amplified WDM signals into two. An optical filter (13A) separates a particular optical signal from one of the two outputs of the beam splitter (12). An optoelectrical converter (14) converts the separated optical signal to a corresponding electric signal. A gain controller (15) controls the gain of the direct amplifier (11) on the basis of the electric signal output from the converter (14). The optical filter 13A may be replaced with an optical variable filter (13B) and controlled by control means when the optical signal for gain control is shut off or sharply varied in wavelength. Because the gain of the direct amplifier (14) is controlled by use of particular one of the plurality of WDM signals, the individual optical signal is controlled to a preselected level even when the number of WDM signals is changed.