Patent ID: 9634768
Date: 2017-04-25
CPC Classifications: H04B

Claim:
1. An optical communication device comprising: an optical modulator having a Mach-Zehnder interferometer with a pair of waveguides; a monitor configured to monitor a modulated light output from the optical modulator; a first controller configured to set a first substrate bias voltage or an amplitude of a first drive signal applied to a first waveguide of the waveguide pair of the optical modulator to a level that provides a first modulation index; and a second controller configured to control a second substrate bias voltage or an amplitude of a second drive signal applied to a second waveguide of the waveguide pair of the optical modulator, based upon an output signal from the monitor, such that a second modulation index for the second waveguide becomes the same or closer to the first modulation index set for the first waveguide.