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:
Dec. 25, 1990
Filed:
Apr. 13, 1989
Applicant:
Inventor:
Katsushi Iwashita, Kanagawa, JP;
Assignee:
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356345 ; 356349 ;
Abstract
A system for a Mach-Zender interferometer which eliminates amplitude modulation of the input light and determines the frequency modulation. Two photodetectors in series are used to receive two outputs of two arms of a Mach-Zender interferometer. The outputs of the photodetectors are summed. The path length difference is controlled by a heater which itself is controlled by a controller. The controller selectively controls the heater based on how much non-zero components are present in the output of the photodetectors.