Two-Dimensional Spectral/spatial Optical CDMA PONs with Hybrid EMC/EPDC Codes

Optical code division multi-access (OCDMA) system is regarded as a good solution of passive optical network (PON), because it provides users to access the network asynchronously with high transmission rate and high security. The performance of OCDMA system is mainly limited by multi-user interference (MUI). Because of using intensity detection, this kind of interference is unavoidable in traditional time-spreading OCDMA systems.he spectral amplitude coding (SAC) OCDMA systems were proposed to eliminate the MUI. When the codes with fixed cross-correlation is used, the MUI could completely eliminates at the receiver. However, the incoherent broadband light source is used in SAC-OCDMA systems, the system performance suffers from phase induced intensity noise (PIIN).urthermore, in these systems, the code length should be made larger in order to accommodate enough simultaneous users. However, the code length is limited by finite bandwidth of light source. The two-dimensional spectral/spatial coding scheme which retains the advantages of SAC-OCDMA systems were proposed to overcome this limitation. However, it still suffers from PIIN.n this thesis, we propose hybrid extended m-sequence code (EMC) / extended perfect difference code (EPDC) codes. And we construct the corresponding OCDMA-PON. Because of some good property of hybrid EMC/EPDC codes, the complexity of the constructed OCDMA PON is reduced. Furthermore, the numerical results show that the OCDMA-PON we proposed has better performance than many other systems.