PMD COMPENSATOR

PROBLEM TO BE SOLVED: To adaptively control EDC based on an optical fiber DGD value that is estimated from a received optical signal DOP and stably compensate waveform degradation by PMD for a long period. SOLUTION: A PMD compensator inputs optical signals that transmit on an optical fiber transmission path and are waveform degraded by PMD, converts them to electric signals and compensates the waveform degradation using EDC. The PMD compensator has one EDC which has PMD compensation characteristics based on a differential group delay DGD of the optical fiber transmission path, or two or more EDCs, the PMD compensation characteristics of which are different from each other, a path to output electric signals without passing through the EDC, a path selection means for selecting a path to output electric signals with passing either one of the EDCs, and a control means for monitoring the polarized DOP of optical signals and generating control signals for path selection of the path selection means to control the path selection means so that the optimum PMD compensation characteristics are achieved based on the differential group delay DGD value of an optical fiber transmission path to the polarized DOP. COPYRIGHT: (C)2010,JPO&INPIT