Patent ID: 11934050
Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
Field: Telecommunications (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A method of controlling an optical modulator that includes a first child modulator configured to generate a first optical signal from a first light beam split from input light, a second child modulator configured to generate a second optical signal from a second light beam split from the input light, and a parent modulator configured to generate a third optical signal from the first optical signal and the second optical signal, the method comprising:
superimposing a first dither signal having a first frequency on a first bias signal and applying the first bias containing the first dither signal to the first child modulator;
superimposing a second dither signal having a second frequency different from the first frequency on a second bias signal and applying the second bias signal containing the second dither signal to the second child modulator;
superimposing a third dither signal having a third frequency different from both the first frequency and the second frequency on a third bias signal and applying the third bias signal containing the third dither signal to the parent modulator;
detecting a first error component having the first frequency, and a second error component having a beat frequency of the second frequency and the third frequency, from the third optical signal;
generating a first error signal from the first error component and the second error component; and
adjusting the first bias signal according to the first error signal.