Impact of dispersion on the performance of optical CDMA transmission system

The impact of fiber chromatic dispersion on the BER (bit error rate) performance of a direct sequence optical code-division multiple-access (COMA) system is analyzed based on the coupled nonlinear Schr0dinger equation (CNLSE). The presented to evaluate considering the expression r of the chromatic dispersion, which will be good for the analysis of the BER. The numerical results show that the system suffers a power penalty of 4.8 dB corresponding to chromatic dispersion index r = 0.4 for seven-chip M-sequence, at a BER of 10-9. It is further noticed that the number of simultaneous users are limited to 24 for r =0.4 and 20 for r = 0.6, for 31-chip M-sequence, at 6 dB power penalty. The result presents that the performance of monopole code-division multiple-access system impacted by chromatic dispersion is the worst. It shows that the bigger the r, the less the user accessed under same conditions.