Multiwavelength optical code division multiplexing

In this paper, we review the previous work in optical code division multiple access (CDMA) systems. Owing to the explosive growth of bandwidth demand in recent years, the current trend in optical communication system designs is to achieve one bit per hertz utilization of the available bandwidth in the optical fiber. Full orthogonality is important in order for optical CDMA systems to achieve high throughput. We describe two spectrally encoded optical CDMA systems which both give us full orthogonality. The throughput of the non-coherent spectral amplitude encoded system is limited by both speckle noise interference and shot noise interference. The multi-wavelength spectral phase encoded system is limited by shot noise only. Performance analysis is also given in this paper.