Optical transmitter and bias control method
AssigneeFujitsu Limited
InventorsHideyuki Matsuura, Kosuke Komaki, Hidetoshi Sato, Katsutoshi Ishidou
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Abstract
An optical transmitter includes: an optical modulator of a Mach-Zehnder type using an InP-based material; a bias controller configured to control a DC bias applied to the optical modulator; a monitor configured to monitor output light of the optical modulator to generate a monitor signal; and a corrector configured to correct a gain of the monitor signal in a direction in which wavelength dependency of insertion loss of the optical modulator is compensated according to a wavelength at a preceding stage of bias control by the bias controller.
Claims10
An optical transmitter comprising:
- an optical modulator of a Mach-Zehnder type using an InP-based material;
- a bias controller configured to control a DC bias applied to the optical modulator;
- a monitor configured to monitor output light of the optical modulator to generate a monitor signal;
- and
- a corrector configured to adjust a gain of the monitor signal such that wavelength dependency of insertion loss of the optical modulator is compensated according to a target wavelength, prior to bias control by the bias controller.
A bias control method comprising:
- superimposing a dither signal on a DC bias of an optical modulator of a Mach-Zehnder type using an InP-based material;
- and
- monitoring output light of the optical modulator to generate a monitor signal including a dither component that fluctuates at a same frequency as the dither signal;
- adjusting a gain of the monitor signal according to a target wavelength so as to compensate for wavelength dependency of insertion loss of the optical modulator;
- and
- executing bias control of the optical modulator using the adjusted monitor signal.
Dependencies are inferred from the claim text.