Optical CDMA system using bipolar codes and based on narrow passband optical filtering and direct detection

Experimental results on an optical spread spectrum system using narrow passband optical filtering, direct detection and post-detection thresholding are presented. BPSK modulation format is employed and electronic pulse sequences representing bipolar codes are used for data encoding. The system takes advantage of the correlation properties offered by use of bipolar codes avoiding however the need for coherent detection and all the problems associated with it. This reception scheme is particularly suitable for combining CDMA with optical FDM in an optical fiber multiple access network.