Closed-Form Expression for the Bit-Error Rate of Spectral-Amplitude-Coding Optical CDMA Systems

The spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) technique is a vital candidate for future optical networks. Until now, there has been no exact analysis for the performance of systems using these techniques, and most researchers use upper and/or lower bounds to obtain the bit-error rate (BER) of these systems. In this letter, a more accurate analysis of the statistics, in terms of the mean and variance, of the decision current in SAC-OCDMA receivers is developed. These statistics are used to evaluate the BER of SAC-OCDMA techniques based on the Gaussian approximation method. Furthermore, the derived BER is evaluated numerically, for two different types of SAC-OCDMA codes, and is shown to fit properly between the upper and lower bounds of the BER.