Deleterious systems effects due to polarization scrambling in the presence of polarization dependent loss

We experimentally verify that this low-frequency polarization scrambling at the transmitter will produce significant system performance degradation for a link with non-negligible values of instantaneous polarisation dependent loss (PDL). We also measure the system BER fluctuation using a recirculating loop testbed that can emulate distributed PDL along an 800-km NRZ transmission link at a 10-Gb/s data rate. We emphasize that network designers might determine that polarization scrambling will be necessary for polarisation mode dispersion (PMD) monitoring, but this could require either the reduction of PDL in all in-line components or the use of a PDL compensator.