The Effects of Polarization-Mode Dispersion on the Phase of the Recovered Clock

The impact of polarization-mode dispersion (PMD) on the phase of the recovered clock in the receiver is analyzed. The effects of first-order PMD on different clock-recovery configurations utilized for return-to-zero (RZ) and non-RZ (NRZ) formats are studied. Closed-form expressions relating the PMD-induced sampling time shift with the differential group delay and the power ratio between the principal states of polarization are obtained for each high-Q filter-based clock recovery. An experimental validation at 10 Gb/s is also shown for the case of NRZ data format