Influence of polarization mode dispersion on the BER performance of DS-OCDMA

In this paper, a theoretical analysis is presented to evaluate the influence of polarization mode dispersion (PMD) on the bit error rate (BER) performance of direct sequence optical code division multiple access system. In this analysis, intensity modulation direct detection technique is employed in single mode fiber operating at 1550nm, and optical orthogonal codes are used as address sequence. Optoelectronic conversion is performed by an avalanche photodiode in an optical correlator receiver. The system BER performance is determined on account of receiver, optical amplifier, and multiuser access interference noises. The power penalty suffered by the system is evaluated at BER of 10⁻⁹ as a function of number of simultaneous users, chip rates, and PMD co-efficient. The system performance is found to degrade more at higher chip rate, and longer fiber length due to the PMD.