Modified decoding and detection scheme for spectral amplitude coding optical CDMA systems

In this reported work, a modified decoding and detection scheme with dispersion compensation is investigated for spectral-amplitude-coding optical code division multiple access (SAC-OCDMA) systems. For simultaneously decoding and compensating the chromatic dispersion of signals in the 40 km-long standard single-mode fibre transmission, based on reconstruction equivalent-chirp method the array configuration of fibre Bragg grating (FBG) segments can be controlled with a quadratic dispersion of -680 ps/nm for an extra time delay. The traditional triple-branch signal detection (TBSD) scheme is then modified and the principle of multiuser interference elimination is theoretically analysed. The simulated results show that, without adding a dispersion compensation device, the modified TBSD scheme adopting the FBG decoder can realise the decoding and detection function in SAC-OCDMA.