GENERATION METHOD FOR DUO BINARY SIGNAL AND OPTICAL TRANSMITTER

摘要

PROBLEM TO BE SOLVED: To provide the generation method of duo binary signals modulatable by binary electric signals and an optical transmitter. SOLUTION: A semiconductor laser 1, a light intensity modulator 2 and a optical phase modulator 3 are cascade-connected. Data signals 6 are branched into two, one is inputted to the light intensity modulator 2 and signal light 4 outputted from the semiconductor laser 1 is intensity-modulated. The other data signal of the ones branched into two is inputted to a precoder 7. The precoder 7 performs code conversion by the logic that output is inverted from '0' to '1' or '1' to '0' when the inputted data signal 6 is '0' and the output is not changed when the inputted data signal 6 is '1'. After the output of the precoder 7 is delayed for 0.5 bit, the intensity-modulated signal light 4 is phase- modulated. The signal light 4 to which both modulation of the intensity modulation and phase modulation is performed is provided with the feature of light duo binary signal light that 'a phase is inverted at the intermediate point of one time slot when the amplitude of the light is '0''.