Optical multilevel signal transmitter, optical multilevel signal transceiver and an optical multi-level signal processing ic

摘要

PROBLEM TO BE SOLVED: To improve distortion of a signal constellation and linearity of a transmission channel by correcting extinction degradation in an orthogonal photoelectric field modulator.SOLUTION: The optical multilevel signal transmitter includes: a multilevel coding circuit that codes an information signal to be transmitted into a photoelectric field modulation signal; an orthogonal photoelectric field modulator that modulates each of non-modulated laser beams on the basis of an in-phase component and an orthogonal component of a photoelectric field modulation signal and outputs its synthetic light as an optical multilevel signal; and an extinction degradation correction circuit that corrects extinction degradation of the orthogonal photoelectric field modulator on the basis of two driving signals of an in-phase driving signal and an orthogonal driving signal to be input into the orthogonal photoelectric field modulator.