Design and analysis of OCDMA system using W/T codes at different bit rates

In this paper, design and simulative analysis of Optical code division multiple access (OCDMA) system using two-dimensional (2D) wavelength/time codes at varying bit rate is done. These pseudo orthogonal matrix codes have been generated by a technique based on the folding of spanning rulers. A correlation is derived between input bit rate with respect to number of users and length of fibre and performance indicators i.e. BER, Quality factor and received optical power. The codes generated by using this technique result in improved performance in terms of quality factor and bit error rate for large number of users at different bit rates not more than 1.5Gbps. This system can support 20 users for 1Gbps, 1.25 Gbps and 1.5 Gbps bit rates for permissible bit error rate less than e-9. For data rate increasing 1.5Gbps the quality of the system deteriorates as high data rate requires more input power, provide lesser reuse of the system and increased level of multiple access interference (MAI) amongst the active users in the system.