Optical Polarization Mode Dispersion Compensator for 40 Gbit/s NRZ and RZ systems

Polarization Mode Dispersion (PMD) represents a major impairment for high bit rate systems resulting in pulse broadening and distortion and leading to system performance degradation if it is not handled properly. PMD is particularly difficult to assess because unlike chromatic dispersion, it varies stochastically in time. Basically, there are two different approaches to mitigate PMD effects: by deploying ultra-low PMD fibres or by using PMD compensators. While the former solution represents an option for new installations, the latter is the preferable solution for in-service systems. In this paper we present an optical PMD compensator able to compensate up to 25 ps of differential group delay in NRZ and RZ 40 Gbit/s systems.