Comparisons between different concatenated codes impact on performance of optical CDMA

In this paper, a method using alterable concatenated code to pre-encode is presented to reduce the impact of system impairment and multiple access interference (MAI) in optical code division multiple access (OCDMA) system, and comprehensive comparisons between different concatenated code type and forward error correcting (FEC) scheme are studied by simulation. In the scheme, we apply concatenated coding to the embedded modulation scheme, and optical orthogonal code (OOC) is employed as address sequence code, an avalanche photodiode (APD) is selected as the system receiver. From numerical results, we can show that the proposed system has good performance at a BER of 10^-9 with a gain of 6.4 dB improvement achieved using the concatenated code as the pre-code.