<title>Performance comparison of different encoding schemes in fiber optic optical code division multiple access (OCDMA) networks and WDM networks with embedded OCDMA</title>

Abstract

In this paper, perfonnance of OCDMA network implemented using single wavelength with optical orthogonal codes (OOCs) and wavelength division multiplex (WDM) networks with embedded CDMA (WeCDMA) has been evaluated. Performance ofthis network is also evaluated when it is implemented with multi-wavelength optical orthogonal codes (MWOOCs) andbit stuffed unipolar m-sequence encoding schemes. In the above evaluation, the receiver is considered to be a PINphotodiodepreceededby an optical amplifier (PIN+OA). Expressions for the probability oferror are derived alter taking into consideration optical multiple access interference (0MM), optical amplifier noise andvarious sources ofreceiver noise. The numericalvalues are computed for practical values ofparameters andthe results are compared for all the above schemes. It is observed that OCDMA networks implemented using WeCDMA with OOC perfonn better thanthe single wavelengthwith OOC forthe samebandwidth expansion. It is also observedthat perfonnance of OCDMA networks using MWOOCs is better than bit stuffed unipolar rn-sequence based networks when number of simultaneous users are less, whereas for large number of simultaneous users the network perfonnance with bit stuffed unipolar msequence encoding scheme is better compared to that with MWOOCs encoding schemes.