PMD-induced impairments in polarization-interleaved WDM systems

Wavelength-division-multiplexing N * 10 Gb/s systems with 12.5-GHz channel spacing should require polarization interleaving (PI). However, fiber PMD can alter PI, giving relevant limitations. We show how impairments are affected by the filtering effect of wavelength-sensitive multiplexers/demultiplexers. For the optimum configuration, an analytical equation relates to the signal Q factor to the instantaneous differential group delay of the link. Hence, PMD-induced impairments can be significantly lower than it was previously estimated.