Design of variable weight 2D-MD code for spectra/spatial OCDMA systems

A variable weight two-dimensional Multi-Diagonal (VW 2D-MD) code is proposed for supporting the Quality of Service (QoS) differentiation in the spectra/spatial Optical Code Division Multiple Access (OCDMA) system. The proposed two-dimensional code is constructed by utilizing the regular one-dimensional Multi-Diagonal (1D-MD) code for spatial coding and the new proposed variable weight MD code as the spectral code. Due to the property of zero cross-correlation, the multiple-access interference (MAI) can be fully eliminated, and the phase induced intensity noise (PIIN) can also be suppressed. In addition, the proposed 2D code can accommodate more active users compared to the 1D VW zero crosscorrelation (ZCC) code. Finally, the simulation setup with the proposed code shows that the performance of the user with larger code weight is better than that of the user with smaller code weight.