Performance degradation in coherent OCDMA due to receivers' bandwidth limit and improvement by using optical thresholding

The limitation of the receiver's bandwidth in coherent TS OCDMA system has been investigated theoretically and experimentally. The receiver's bandwidth limitation will result in severe performance degradation due to the accumulation of the MAI and secondary beat noise. Applying optical thresholding technique in the system could eliminate the out-of-peak MAI and secondary beat noise to improve the performance significantly. The experimental results agree with the theoretical predictions very well. Therefore, it is essential to employ optical thresholder in practical coherent TS OCDMA system with a receiver that performs data-rate detection.