Evaluation of beat noise in OCDMA system with non-Gaussian approximated method

With the development of phase encoding technologies, beat noise becomes one of the most predominant limitations of optical code division multiaccess (OCDMA) systems. In order to analyze beat noises' impact more accurately, a non-Gaussian analysis with consideration of a decision variable's moment generation function is first introduced in this paper to evaluate both the multiaccess interference and the beat noises simultaneously, where prime, secondary, and partial coherent beat noises are discussed in detail. In this paper, the saddle-point approximation (SPA) method is first utilized to investigate beat noise's impact on an OCDMA system. Comparison of probability density functions as well as bit error rates between the proposed method and the traditional Gaussian approximation method is given here. The resultant achievement shows the outstanding performance of SPA on this occasion, which proves the necessity of such a moment generation function-based non-Gaussian analysis