Utilization of LDPC Code and Optical Hard-Limiter in OCDMA Communication Systems

In this paper, we investigate the utilization of low-density parity-check (LDPC) code and optical hard-limiter in OCDMA communication systems. Since the multiple access interference will impose significant penalty on system performance, using optical hard-limiter is an effective countermeasure to relieve this adverse impact. To further increase the aggregate capacity, the LDPC code is employed as an error correction mechanism that can allow more simultaneous users accommodated in the network. As the aggregate capacity and system complexity are the main considerations in practical system design, both of which are mutually trade off. Utilization of LDPC code and optical hard-limiter can effectively reduce the system complexity to reach the maximum aggregate capacity. Our proposed scheme can accommodate large number of users in the network simultaneously and support the traffic asynchronously with each user. Furthermore, the aggregate capacity can reach above 100 Gbps; therefore, it is the preferable way as the platform for fiber distribution network in some applications.