OPTICAL TRANSMITTER, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL COMMUNICATION METHOD

摘要

In a polarization multiplexed optical communication system which uses an optical digital coherent communication method, cases occur in which reproduction of a transmission signal becomes difficult due to an optical phase modulation method used, and therefore, this optical transmitter is provided with: a first direct light modulator which applies phase modulation to a first continuous light in order to output a first transmission light; a second direct light modulator which applies phase modulation to a second continuous light which belongs to the same frequency band as the first continuous light in order to output a second transmission light; an optical phase difference imparting unit which generates a time-varying optical phase difference between the first transmission light and the second transmission light; and a polarization multiplexing unit which polarization-multiplexes the first transmission light and the second transmission light in a state in which the polarizations are made orthogonal to each other so as to output polarization multiplexed transmission light.