All optical wavelength conversion of dual users CO-OFDM system based on FWM in cascade HNLFs

Abstract

We propose a scheme for all optical wavelength conversion (AOWC) of dual users coherent optical orthogonal frequency division multiplexing (CO-OFDM) system with error bits free. The scheme is based on four wave mixing (FWM) in high nonlinear fiber (HNLF). In this scheme, cascade HNLFs are used to generate twice FWM processes. The simulation results show that the wavelength converted signal can be obtained successfully. Optical spectra and constellation diagrams of the proposed wavelength conversion (WC) system indicate a better error tolerance and resistance to phase noise compared with that of a system without WC. The bit error rate (BER), error vector magnitude (EVM), and optical signal-to-noise ratio (OSNR) penalty of the CO-OFDM system with AOWC are analyzed. The proposed scheme is also validated after the optical fiber transmission and in single user CO-OFDM systems based on BER performance and constellation diagrams, respectively.