PMD compensator with second-order PMD mitigation using mode-coupled fixed delay

We investigate a very simple second-order polarization-mode dispersion (PMD) compensator with a mode-coupled fixed delay that has a fixed first- and second-order PMD (SOPMD). The PMD compensator (PMDC) was compared to a conventional simple PMDC (SPMDC) and another type of second-order PMDC in simulations of 40-Gb/s nonreturn-to-zero (NRZ) and return-to-zero transmission systems. It was found that our PMDC has better performance than the conventional SPMDC in both formats, and further, has better performance than another type of second-order PMDC in NRZ format. In addition, it was revealed that the combination of the two second-order PMDCs has very good performance of SOPMD compensation.