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:
Jun. 16, 1998
Filed:
Dec. 27, 1996
Tsutomu Tajima, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a wavelength multiplexing optical transmission device, first and second optical transmission boards output optical signals which have wavelengths different from each other and on which different sine-wave signals are superposed. The optical signals are coupled by an optical coupler, then divided into two lights by an optical divider. One optical signal is amplified by an optical amplifier. the other optical signal is converted into an electrical signal by a photodiode. The sine-wave signal components are extracted by first and second bandpass filters with the existence of the extracted signals being detected by output detectors. An adder output a reference voltage signal with a voltage according to the number of signals detected. A gain control circuit controls the amplification gain based on a voltage value corresponding to the intensity of an optical signal to be output and the reference voltage value, so that the level of output light can be controlled according to the number of optical signals.