M-ary FSK signalling for incoherent all-optical CDMA networks

We present a novel approach for the combination of M-ary FSK data signalling with incoherent all-optical code division multiple access (CDMA) systems. In contrast to well-known pulse position modulation (PPM) schemes no critical frame synchronisation is necessary and less frequencies than in wavelength division multiplexing (WDM) are needed, resulting in an improved performance. The M-ary source coding leads to a lower repetition rate of the used tunable mode locked laser or to a higher data rate than in OOK/CDMA systems. The filter bank of the maximum likelihood detector can be easily realized by arrayed waveguides. The theoretical performance for optical orthogonal codes (OOC) is analysed and a comparison to OOK and PPM is given.