Optical domain multiuser interference estimation for spectral phase encoding optical fibre CDMA systems

In this paper, an effective technique for reducing the multi-user interference (MUI) in spectrally-phase-encoded optical code division multiple access (SPE-OCDMA) systems has been proposed. In this method the effect of MUI signal on the main user´s signal has been decreased using multiuser interference detection (MID). Two structures have been introduced for accomplishing MID and degrading its destructive effect on the decoded ultra-short light pulse; temporal multiuser interference estimation (TMIE) and nonlinear multiuser interference estimation (NMIE). Both of these methods utilize two photo-detectors for estimating the MUI signal. In spite of simple structure of these two receivers, their performance analysis shows an improved performances comparing to other receivers.