Patent ID: 11888526
Assignee: FUJITSU LIMITED
Field: Optics (Instruments)
Classification: CPC H  G | IPC G  H

Claim 7:
8. A communication apparatus comprising:
an optical transceiver; and
an electrical or electronic device provided to operate the optical transceiver,
wherein the optical transceiver includes an electro-optic modulator, a monitor circuit that monitors output light of the electro-optic modulator, and a processor that controls a bias voltage of the electro-optic modulator using a monitoring result of the monitor circuit,
wherein the processor superimposes a first dither signal of a first frequency and a second dither signal of a second frequency, which is different from the first frequency, onto the bias voltage in a time sharing manner, calculates a first control error based on a first component oscillating at the first frequency and a second control error based on a second component oscillating at the second frequency from the monitoring result, and determines a control value for controlling the bias voltage using the first control error and the second control error,
wherein the monitor circuit has a photodetector that detects a portion of the output light of the electro-optic modulator, a first filter that extracts the first component oscillating at the first frequency from an output of the photodetector, and a second filter that extracts the second component oscillating at the second frequency from the output of the photodetector, and
wherein the processor synchronizes switching between the first dither signal and the second dither signal with switching between the first filter and the second filter.