OPTICAL MODULATION DEVICE

摘要

PROBLEM TO BE SOLVED: To synthesize an intensity modulation signal and a phase modulation signal with simple constitution and low loss and to enable the formation of the driving signal of an optical modulator by branching the light carrier from a light source, optically modulating the branched light carriers with plural synthesis signals, joining the modulated light carriers and outputting the optical modulation signal. SOLUTION: A 180 deg. hybrid 16 which is a two-input two-output passive circuit branches the inputted intensity modulation signal to a first electric signal of an in-phase and a second electric signal of an antiphase and branches the phase modulation signal inputted to another input terminal to third and fourth electric signals of the in-phase. The synthesis signal of the first and fourth electric signals and the synthesis signals of the second and third electric signals are outputted. The optical modulator 1 of a two-electrode LN-MZ type branches the light carrier from the light source 15 outputting the light of specified intensity and optically modulates the branched two light carriers by the two synthesis signals from the 180 deg. hybrid 16, joins the modulated two light carriers and outputs the optical modulation signal.