Performance Analysis of Wavelength/Time Matrix Encoding System for 32 Users Optical CDMA Network

The Optical Code Division Multiple Access (OCDMA) system plays an important role in long haul and high speed communication networks like LAN and MAN. These systems have advantage of large capacity, high speed and huge bandwidth. The major available multiple access techniques are TDMA, WDMA and CDMA. Both TDMA and WDMA system require time or frequency management system however the CDMA system does not require any centralized control and thereby reduce the complexity of the system. Optical CDMA combines flexibility of the CDMA technique with the large bandwidth of the fiber medium to achieve the high-speed connectivity. The establishment of OCDMA needs to overcome the code orthogonality problem and also in 1-D optical orthogonal codes, the ratio of code length to the code weight grows rapidly as the number of users increases. Incoherent OCDMA scheme based on wavelength/time (W/T) codes has been proposed in this paper. Using a power normalizer, a W/T OCDMA system is built to support 32 simultaneous users for a 180 km long link with bit error rate (BER) = 10-26.