A new family of 2D wavelength/time codes with large cardinality for incoherent spectral amplitude coding OCDMA networks and analysis of its performance

Abstract

A new family of two-dimensional wavelength/time codes (2D-W/T-MQC/MQCs) and its system structure of encoder/decoder are proposed, which is based on tunable optical fiber delay lines (TOFDLs) and fiber Bragg gratings (FBGs). Multiple-access interference (MAI) can fully be eliminated by using a wavelength/time balanced detector structure at the receivers. Furthermore, the performance of the system is also analyzed by taking into account the phase-induced intensity noise (PIIN), shot noise, and thermal noise. The simulation results reveal that the new code family possesses higher signal-to-noise ratio (SNR) and lower bit-error rate (BER) than the family of one-dimensional spectral amplitude coding modified quadratic congruence codes (1D-SAC-MQCs) and that of the two-dimensional wavelength/spatial M-matrices codes (2D-W/S-M-Matrices) so that a larger number of subscribers can be supported simultaneously. Additionally, the 2D-W/T-MQC/MQC system requires less signal power for each light source under the same error-free condition. As a result, the network based on the new code family will support more active users and utilize the frequency bandwidth more efficiently.