Signal state of polarization controlling optical transmission system

摘要

Polarization control is used in an optical communication system that includes as repeaters optical amplifiers whose output signal power fluctuates according to the state of polarization of signal light L1. The transmission system comprises means 8 for detecting the bit error rate of a received signal which deteriorates as the polarization fluctuates. A feedback signal from the detector is used to change the polarization 3 to an orthogonal polarization state.