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. 04, 2003
Filed:
Mar. 13, 2002
Applicant:
Inventors:
Hitoshi Hatayama, Yokohama, JP;
Chisai Hirose, Yokohama, JP;
Masayuki Nishimura, Yokohama, JP;
Makoto Katayama, Yokohama, JP;
Assignee:
Sumitomo Electric Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B 6/26 ; G02B 6/12 ; G02F 1/025 ;
U.S. Cl.
CPC ...
G02B 6/26 ; G02B 6/12 ; G02F 1/025 ;
Abstract
A main optical path and an auxiliary optical path which are formed in a substrate are optically coupled to each other with a plurality of optical couplers, so as to constitute a Mach-Zehnder interferometer. By controlling the temperature regulation of main and auxiliary optical paths effected by heaters, a control unit regulates the transmissivity of light across an optical input end and an optical output end. Respective optical path lengths of the main and auxiliary optical paths are set so as to lower birefringence when optical loss becomes greater.