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:
Sep. 21, 1999
Filed:
Aug. 07, 1996
Applicant:
Inventors:
Takaaki Ogata, Tokyo, JP;
Yukio Michishita, Tokyo, JP;
Assignee:
NEC Corporation, , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04J / ;
U.S. Cl.
CPC ...
359125 ; 359133 ;
Abstract
At a transmission section, different frequencies ranging from f1 to fn corresponding to n channels are generated as channel information, respectively. The signal light (.lambda.1 to .lambda.n) of each channel is modulated at the corresponding frequency (f1 to fn) and multiplexed. At a reception section, in case of selecting the channel of the signal light .lambda.1, the wavelength selection characteristic of a filter is sweep controlled for detecting the frequency f1. The wavelength selection characteristic at the f1 detection is kept as the wavelength selection characteristic of the filter.