Analytical Evaluation of the Effect of Cross-Polarization-induced Crosstalk on the BER Performance of a PDM-QPSK Coherent Homodyne Optical Transmission System

Abstract

Abstract An analytical approach is developed to find the effect of cross-polarization (XPol)-induced crosstalk on the bit error rate (BER) performance of a polarization division multiplex (PDM) quadrature phase shift keying (QPSK) optical transmission system with polarization diversity receiver. Analytical expression for the XPol-induced crosstalk and signal to crosstalk plus noise ratio (SCNR) are developed at the output of polarization diversity PDM-QPSK coherent optical homodyne receiver conditioned on a given value of mean misalignment angle. Considering Maxwellian distribution for the pdf of the misalignment angle, the average SCNR and average BER are derived. Results show that there is significant deterioration in the BER performance and power penalty due to XPol-induced crosstalk. Penalties in signal power are found to be 8.85 dB, 11.28 dB and 12.59 dB correspondingly for LO laser power of −10 dBm, −5 dBm and 0 dBm at a data rate of 100 Gbps, mean misalignment angle of 7.5 degree and BER of 10−9 compared to the signal power without crosstalk.