New code structures based on coherent and incoherent sources for spectral amplitude coding-OCDMA systems

Abstract

A new code of optical code division multiple access (OCDMA) based on Spectral Amplitude Coding (SAC) is described and analyzed. The coding technique is called Random Diagonal "RD" code. One of the important properties of this code is that the cross correlation at data segment is always zero, which means that Phase Intensity Induced Noise (PIIN) is reduced. From the construction of RD code sequence, we can see that the RD code is constructed using code segment and data segment. Using this code property, RD code is implemented using coherent source (multilaser) and incoherent source (light emitting diode) for the code segment and data segment respectively. RD code using two multi-sources (inchoherent and coherent) can be considered as an effective way for maximizing the capacity while minimizing the cost of SAC-OCDMA. It is shown that the system using this new code matrices not only suppresses PIIN, but also allows a larger number of active users compared with other codes.