Suppression of optical beat interference using synchronised CDMA technique and in-band clipping carrier

Abstract

The authors propose adding a coherent in-band clipping carrier to a previously demonstrated Walsh-code-based synchronised CDMA (S-CDMA) technique to further suppress the optical beat interference (OBI). Experimental results showed thar a negligible system power penalty can be achieved even when the OBI-induced intensity noise was as high as -90.9dB/Hz. In addition, a large system dynamic range of 10dB can tx obtained to relax the tight power control requirement on S-CDMA signals.