Optical signal transmission device, optical signal polarization modulation device, optical signal transmission method, optical signal polarization modulation method and transmission system

摘要

The present invention provides a method and apparatus for modulating a polarization of an optical signal. A polarization modulator receives an optical signal on the already modulated data at a predetermined frequency. The polarization modulator is phase modulated in the modulated data on the optical signal and modulates the polarization state of the optical signal at the same frequency of the same predetermined frequency. The polarization modulation is performed so that the average value of the polarization states on each modulation cycle is substantially " 0 "