PMD monitoring in WDM systems for NRZ data using a chromatic-dispersion-regenerated clock

Abstract

We demonstrate a polarisation mode dispersion (PMD) monitor for NRZ signals that measures the effects of PMD on a chromatic-dispersion-generated clock tone. In NRZ transmission, no clock tone appears at a detector if the link chromatic dispersion is well compensated. In our method, we introduce fiber-Bragg based chromatic dispersion (negligible PMD) in the feedback loop of the PMD compensator to generate a 10 GHz clock tone within an NRZ signal.