A novel quasi-synchronous coherent time-spreading optical CDMA system

In coherent time-spreading OCDMA, beat noise is the main performance limitation. We propose a novel quasisynchronous coherent time-spreading optical CDMA, where the synchronization among users can be controlled within permissible time delay. Within permissible time delay, the mean intensity of aperiodic cross-correlation equals zero, and the beat noise can be removed. Simulation of four simultaneous users employing LA sequence (156, 8,16) is demonstrated, where the fiber link consists of 10km single-mode fiber, plus 1 km Dispersion Compensating Fiber. It can be seen that, beat noise can be removed in quasi-synchronous coherent time-spreading optical CDMA system.