Development and performance improvement of a novel zero cross-correlation code for SAC-OCDMA systems

In order to improve the performance of the Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) system, a zero cross-correlation (ZCC) code named double weight multi-diagonal (DW-MD) is proposed with constant weight (CW) or variable weight (VW). Mathematical results illustrate that it is feasible to reduce the number of filters without sacrificing system performance by using the CW DW-MD code instead of the multi-diagonal (MD) code. And for the VW DW-MD code, the supportable number of users for lower code weight WL (3) at bit error rate (BER) of 10−3 (voice) is 43, medium code weight WM (4) at BER of 10−9 (data) is 29, and higher code weight WH (5) at BER of 10−12 (video) is 32. Finally, the analysis about the position of chips “1” is given, and the simulation setups show that the CW DW-MD code outperforms the MD code when Gaussian optical filter is used.

PIIN Cancellation Using a Novel Receiving Architecture for Spectral/Spatial SAC-OCDMA System

Increasing the number of users presents a limitation in one-dimensional (1D) spectral amplitude coding (SAC) for Optical Code Division Multiple Access (OCDMA) system. In order to overcome this disadvantage, a new architecture of the two-dimensional wavelength/spatial SAC-OCDMA system using the multi-diagonal (MD) code has been proposed. The 2D-MD code possesses the same properties of 1D-MD code, which leads to total suppression of the multiple access interference. Unlike conventional receivers used in precedent studies, where the phase-induced intensity noise (PIIN) is a drawback, the suggested structure not only eliminates PIIN but reduces the system architecture. The results show that the user’s number reached by the proposed system is the user number’s multiplication of the 1D system and the couplers’ number. Moreover, the new 2D-MD system presents good performances at the high data rate.