An Enhanced Detection Technique for Spectral Amplitude Coding Optical CDMA Systems

In this letter, we investigate the use of the multiphotodiode balanced detection (MPBD) scheme proposed by Williams in IEEE Photonics Technology Letters, (volume 8, pages 148-150, January 1996), to reduce phase-induced intensity noise (PIIN) in spectral amplitude coding optical code-division multiple access (SAC OCDMA). The MPBD is based on balancing the power reaching the balanced detector by utilizing multiple numbers of photodiodes. Since PIIN is signal dependent, by reducing the power reaching each photodiode, the overall PIIN can be reduced. Results show that MPBD outperforms the conventional balanced detector at a cost of added complexity.