OPTICAL MODULATOR, CONTROLLING METHOD AND APPARATUS THEREOF, OPTICAL TRANSMITTER, AND OPTICAL TRANSMISSION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an optical modulator capable of outputting a quadratic amplitude modulation (QAM) signal light having a 4Nvalue with good signal quality.

SOLUTION: The optical modulator branches an input light into four lights in an optical branching section 1, and then phase-modulates each of the branched lights in phase modulation sections 21 to 24, and couples respective phase-modulated lights in an optical coupling section 3 to generate a 16QAM signal light. At this time, a relative difference of optical phases of respective phase-modulated lights is variably adjusted by an optical phase adjusting section 4. Moreover, a power ratio of respective phase-modulated lights is variably adjusted by an optical power adjusting section 5.

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