Performance analysis for an optical CDMA system in presence of fiber chromatic dispersion

Abstract

Optical code division multiple-access technique has recently received substantial attention in fiber optic communication for its asynchronous access, privacy and security. In this thesis, a detail analytical formulation is presented to study the impact of fiber chromatic dispersion induced on the bit error rate (BER) performance and eye diagram in terms of power penalty for direct sequence optical code division multiple access (DSOCDMA) transmission link using an intensity modulated direct detection (lM/DD) sequence inverse keying (SIK) optical correlator receiver. The analysis is carried out considering the influence of fiber chromatic dispersion on the rectangular chips of the pseudo-noise (PN) sequence which results in interchip interference (lCI). 7 chip msequence and 32 chip Gold sequence are used in the simulation with number of simultaneous user as a parameter at a chip rate of IOGchip/s. The simulation results reveal that with the increase in fiber chromatic dispersion, the system performance degrades and as a result higher power penalty is required, measured at a BER of 10-9. The system can accumulate larger number of users at lower value of chromatic index. The system performance is also dependent on the type and length of sequence. The position and number of'I' in a same length chip sequence effect the power penalty.