Joint CD and PMD monitoring based on a pair of low-bandwidth coherent receivers.

Abstract

A joint chromatic dispersion (CD) and 1st order polarization mode dispersion (PMD) monitoring technique for both a coherent and a non-coherent single carrier system based on a pair of cost effective low-bandwidth coherent receivers is proposed and experimentally demonstrated. By jointly detecting the narrow band around ± 1/2 baud rate, the CD and PMD can be estimated simultaneously by time domain correlation and Stokes space rotational angle recovery, respectively. The CD estimation range is theoretically infinite and the PMD estimation range is limited to the maximum of 1/2 symbol period. Simulation results show that for a 28 G baud dual-polarization (DP)-16QAM transmission system, with dual 1 GHz coherent receivers, the monitoring error for CD and differential group delay (DGD) is 30 ps/nm and 0.5 ps, respectively. We also experimentally verified it for a 12 GBit/s NRZ-OOK transmission system with a full-bandwidth coherent receiver and two 1 GHz digital filters to simulate dual 1 GHz coherent receivers. The monitoring error for CD and DGD is 60 ps/nm and 1.5 ps, respectively.