Performance of a CPDM-QPSK Coherent Homodyne Optical Transmission System due to Cross Polarization Effects

Analysis is achieved for an optical coherent homodyne Circular Polarization Division Multiplexing Quadrature Phase Shift Keying (CPDM-QPSK) transmission system taking into consideration the influence of the crosstalk due to cross polarization induced by random misalignment of the SOPs. Analysis is presented to find the expression at the output of the Signal to Cross-talk plus Noise Ratio (SCNR) of a coherent homodyne QPSK receiver. Results of Bit Error Rate (BER) performance are evaluated taking the Maxwellian distribution of the random misalignment angles into account. A significant degradation is seen in the performance of BER from the results due to the effect of cross polarization. It is found that, the system suffers power penalty of 7.43, 13.41, 18.78, 32.29 dB for misalignment angle of 20, 30, 40 and 60 degrees respectively at BER of 10
^-9
by fixing the local oscillator power at 1.0mW.