OPTICAL MODULATOR, OPTICAL TRANSMITTER, AND METHOD FOR ADJUSTING BIAS

摘要

PROBLEM TO BE SOLVED: To provide an optical modulator capable of reducing a loss and reducing a difference in amplitude levels of optical signals of an I channel and a Q channel.

SOLUTION: This optical modulator includes: a first MZ optical modulator 5a; a second MZ optical modulator 5b; a first optical amplifier 6a amplifying the output of the first MZ optical modulator 5a at an amplification factor based on a first bias signal; a second optical amplifier 6b amplifying the output of the second MZ optical modulator 5b at an amplification factor based on a second bias signal; an optical phase adjuster 7 phase-rotating the output of the second optical amplifier 6b; an optical multiplexer 8 multiplexing the output of the first optical amplifier 6a and the output of the optical phase adjuster 7; and a second DC bias correction section 17 generating a first pulse signal and a second pulse signal that are complementary to each other and acquiring a first bias value and a second bias value based on an intensity change in the output signal of the optical multiplexer 8. The first pulse signal is superimposed on the first bias signal, and the second pulse signal is superimposed on the second bias signal.

COPYRIGHT: (C)2012,JPO&INPIT