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:
Apr. 21, 1998
Filed:
Nov. 06, 1995
Applicant:
Inventor:
Arihide Noda, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G02F / ; G02F / ;
U.S. Cl.
CPC ...
345 84 ; 359249 ; 385-5 ;
Abstract
An optical modulation device comprises an optical modulator in which the operating point is varied according to a bias voltage. A phase deviation of an operating point from a selected optimal operating point is detected by a phase comparator based on an output light of the optical modulator. The bias voltage is generated within a predetermined voltage range by a DC amplifier so as to reduce the phase deviation. A reset circuit resets the bias voltage at the ground voltage associated with the selected optimal operating point when the optical modulator is powered up and passes the bias voltage to the optical modulator at all other times.