Performance analysis of coherent bandwidth-limited time-spreading encoding OCDMA system employing pulse-position modulation

Time-spreading (TS) phase encoding optical code division multiplexing access (OCDMA) systems with pulse-position modulation (PPM) signalling are investigated, the multiple access interference, optical beat noise and bandwidth limitation of receiver are considered. The authors also compare the performance of the PPM system with that of the conventional on-off keying (OOK) system with optimum threshold detection. Numerical results show that there exists an optimum pulse-position multiplicity for the PPM OCDMA system, and the corresponding PPM scheme is superior to OOK scheme in the coherent bandwidth-limited TS OCDMA system under the chip time constraint.