Optical transmitter and optical transmission system

摘要

The present invention suppresses to a minimum the degradation of the transmission quality caused by chromatic dispersion characteristic of an optical transmission medium, and the interplay between the chromatic dispersion and non-linear optical effects in dense WDM transport systems. A baseband input data signal is precoded in advance by a pre-coding unit (2), phase modulation is carried out using a precoded signal by the optical phase modulating unit (3), and the phase modulated optical signal is converted to an RZ intensity modulated signal by the optical filter unit (5) that performs phase-shift-keying to amplitude-shift-keying conversion. For example, an optical phase modulating unit (3) generates an encoded DPSK phase modulated signal using a differential phase shirt keying (DPSK) format, and a phase modulated signal is converted to an RZ intensity modulated signal by the optical filter unit (5) disposed downstream of the optical phase modulating unit (3).