Impact of chipshape on the performance of DS-OCDMA in dispersive fiber medium

Chipshape-dependent bit error rate (BER) performance of direct sequence optical code division multiple access is analytically studied in fiber optic communication with cascaded in-line optical amplifiers in presence of group velocity dispersion. In our analysis, supper-Gaussian, and Hyperbolic-Secant shaped optical orthogonal codes are employed as address sequence. Avalanche photodiode is used in an optical correlator receiver for optoelectronic conversion. The BER performance is determined as a function of received signal power, number of simultaneous users, and fiber length on account of receiver, optical amplifier, and multiuser access interference noises. The numerical results show that the BER performance of the system is highly dependent on the chipshape. The power penalty suffered by the system is evaluated at BER of 10^-9. It is found that the proposed system suffered minimum penalty when Hyperbolic-Secant shaped chip used instead of supper-Gaussian shaped chip.