Simulative analysis of 2-code keying approach using Walsh Hadamard codes to enhance security and reduce dispersion in OCDMA system

In this paper, a simulative analysis is presented to evaluate the performance of Optical Code Division Multiple Access (OCDMA) system to enhance security and reduce dispersion using 2-code keying i.e. bipolar coding approach. In this analysis for the first time we have used Walsh Hadamard codes (excluding the code words consisting of all “ones”) in bipolar arrangement to ensure successful transmission of OCDMA signal and to prevent wire tapper simultaneously for an authorized user as with single authorized user in the system transmitting information at a particular instant of time using single code keying approach there is always a possibility that a wire tapper can easily retrieve the information without any effort. Performance of the system is reported for variation in fiber length in form of Quality Factor and received optical power and values of these parameters are plotted on graphs. Investigations reveal that the proposed approach enhances the security of the system that is further proved by the eye diagrams.