The laser linewidth effect on interference cancellation in asynchronous coherent OCDMA systems

Interference cancellation within both detection and carrier phase estimation processes asynchronous coherent OCDMA systems is proposed. At the receiver, knowledge gained from the synchronization and detection is used to rebuild and remove the interference from the detected signal. The key advantage of the proposed system is that it can be performed directly in the electrical domain. Since an essential implementation issue with coherent optical communications is generated by the linewidth of the laser source, the effect of laser linewidth on the cancellation is investigated. By applying cancellation within the phase estimation, the stringent requirements with respect to the laser linewidth can be relaxed