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.