Patent ID: 9548818
Date: 2017-01-17
CPC Classifications: G02F,H04B

Claim:
1. An optical modulator comprising: an optical branch structure which branches an input light into two optical signals via two arms; an optical phase modulator which applies an operating voltage to at least one arm so as to modulate an optical phase of an optical signal transmitted via at least one arm; an optical phase adjuster which applies a voltage below the operating voltage to at least one arm so as to adjust an operating point; and an optical coupling structure which combines optical signals output from the optical phase adjuster so as to produce an output light, wherein the optical phase adjuster includes an optical phase coarse adjuster and an optical phase fine adjuster, wherein the optical phase coarse adjuster applies a voltage below the operating voltage to at least one arm so as to change an optical phase of an optical signal transmitted via at least one arm by 180° or more, and wherein the optical phase fine adjuster applies a voltage below the operating voltage to at least one arm so as to changer an optical phase of an optical signal transmitted via at least one arm by 90° or less.