Mitigating the impact of group velocity dispersion in a time-spreading optical CDMA system

Optical code division multiple access (OCDMA) has received increasing attention for applications in modern optical networks. The performance of OCDMA systems is strongly affected by fiber group velocity dispersion (GVD) because of using ultra short optical pulses. In this paper, a new investigation on the effectiveness of using a fiber bragg grating (FBG) with a chirped optical period at the transmitter of a time-spreading OCDMA system to mitigate the effect of GVD is carried out. FBGs with different chirp profiles are employed in order to find the best profile which enhances the system performance more effectively compared to other ones. The performance of the system is evaluated through BER parameter. Simulation results show a great improvement in the system performance when the FBG is used at the transmitter and an error free transmission is obtained for longer distances.