Implementation of spectrally-coded FBG-based coder/decoder optical CDMA network to reduce the effect of four wave mixing.

Our proposed Optical CDMA network is implemented by spectral-coding of incoherent broadband optical sources. We have utilized the transmissive spectrum characteristics of FBG (Fiber Bragg Grating) to design FBG encoder/decoder. In our design, we have not used any circulator; thereby reducing the cost as well as power loss issue is resolved to a great extent. Signal at the receiver is separated with acceptable bit-error rate ≤10 −9 . The coding and decoding method is based on spectral-amplitude coding of FBG. Here FBG are used to control and modify the amplitude and phase spectrum of broadband incoherent optical signal. The effect of FWM (four wave mixing) is avoided to a larger extent by using this optical CDMA coding technique. Simulation results too confirmed better results in terms of Q factor, SNR and bit error rate in favor of NRZ modulation format compared to other formats. [ABSTRACT FROM AUTHOR]