Cross-polarization induced crosstalk impact analysis on the BER performance of 100-Gbps CPDM 8-QAM CO-FOC system over unrepeatered 100-km SSMF link

Abstract

This proposed article presents a comprehensive investigation of a coherent optical (CO) circular-polarization division multiplexed (CPDM) 8-quadrature amplitude modulation (8-QAM) for the fiber optic communication (FOC) system over an unrepeatered 100 km SSMF link to find the impact of cross-polarization (XPol) induced crosstalk by arbitrary misalignment of the states of polarization (SOPs) on the bit error rate (BER) performance. A thorough study with a mathematical analysis is demonstrated, considering the Maxwellian distribution for the mean misalignment angle, to acquire the output expression of the signal to cross-talk plus noise ratio (SCNR) and average BER for a CO homodyne CPDM 8-QAM receiver. Numerical simulations exhibit that BER performance deteriorates due to the XPol effects. Results show that the system experiences a power penalty for the mean misalignment angle to acquire a definite BER of 10−9 for a fixed local oscillator power. Besides, a detailed comparison between the existing PDM-QPSK and our proposed CPDM 8-QAM model is elucidated where our proposed model is significantly better than the existing model in terms of SCNR-BER performances, spectral-efficiency (SE) and capacity of the system as well.