Mitigation of Polarization Mode Dispersion in an Optical Heterodyne CPFSK Transmission System using Line Codes

Abstract

A theoretical analysis for evaluating the performance of line codes in the polarization mode dispersion (PMD) mitigation of an optical heterodyne continuous phase frequency shift keying (CPFSK) transmission system with delay demodulation receiver is presented. It accounts for the combined effects of signal phase distortion due to PMD and chromatic dispersion in a single mode fiber. The analysis is carried out for three different linecoding schemes, i. e., alternate mark inversion, order-1 and delay modulation coding, to investigate the efficacy of the linecoding in counteracting the effect of PMD in CPFSK optical transmission system. Performance results are evaluated in terms of average bit error rate (BER) with line codes and compared with NRZ-CPFSK system at a bit rate of 10 Gbit/s considering Maxwellian probability distribution for the mean differential group delay (DGD) due to PMD. The results show that the penalty improvement of line coded systems is within 0.5 dB to 1.95 dB with respect to NRZ data for mean DGD 30 ps and at a BER of 10 -9 . .