Performance evaluation of a coded CDMA optical system

The performance of a coherent code division multiple access (CDMA) optical fiber communication system is degraded by the phase noise of the semiconductor lasers and by multiple access interference (MAI). This paper examines the effects of phase noise on the performance of a CDMA optical system. Results show that the combined effects of MAI and laser phase noise impose a very low limit on the number of simultaneous users. We investigate the possibility of increasing the receiver sensitivity using convolutional coding with Viterbi decoding, and show that coding significantly improves system performance, and allows for relaxation of the laser linewidth.