Comparative Performance Analysis of FWM Effect in DWDM System

Abstract

The non linear effects degrade the system performance. Non linearity effects arose as optical fiber data rates, transmission lengths, number of wavelengths and optical power levels increased, there study become important in DWDM system. The two types of nonlinearities occur in optical fiber are:-  Stimulated scattering such as SRS and SBS  Optical Kerr effect, due to changes in the refractive index of fiber with optical power Depending upon the type of input sign Kerr-non-linearity represented in three different types of effects such as Self-Phase Modulation (SPM), Cross-Phase Modulation (CPM) and Four- Wave Mixing (FWM). At high power level, the inelastic scattering phenomenon can induce stimulated effects such as Stimulated-Raman Scattering (SRS) and Stimulated Brillion Scattering (SBS). Four-wave mixing (FWM) is one of the dominating degradation effects in wavelength-division-multiplexing (WDM) systems with dense channel spacing and low chromatic dispersion on the fiber. If in a WDM system the channels are equally spaced, the new waves generated by FWM will fall at channel frequencies and, thus, will give rise to crosstalk. Four-wave mixing (FWM) is a parametric process in which different frequencies interact and by frequency mixing generate new spectral components. In this dissertation single and combined effect of input power, effective area, length of fiber and channel spacing are studied on FWM in Dense Wavelength Division Multiplexing (DWDM) optical communication system. The simulation is carried with eight channels in Optisystem software. Results show that increasing fiber length, effective area, channel spacing and decreasing input power reduces four wave mixing power to -70dbm. BER and Q factor are estimated using BER analyzer at the receiver side