Optical PMD compensation performance: numerical assessment

Our study provides an extensive comparison of many proposed polarisation mode dispersion (PMD) compensation schemes in terms of pure ´BER performance´. Our study is, of course system, dependent, but it gives important hints on their behavior. We warn, that we did not optimize the compensator´s differential group delay (DGD) so that we underestimate SC and 2PMFs´s performance. We proved that the extrapolations usually done from CP=10^-3 are fairly optimistic, which contributes to (with sub-optimal DGD) the divergence of our results from previously published work. We established that a compensation technique can not be separated from a feedback signal, which is sometimes more important that the compensator itself.