Four Wave Mixing In DWDM Optical System

Optical nonlinearities give rise to many ubiquitous effects in optical fibres’. These effects are interesting in themselves and can be detrimental in optical communication. In the Dense Wave length division multiplexing system (DWDM) the nonlinear effects plays important role .DWDM system offers component reliability, system availability and system margin. DWDM system carries different channels. Hence power level carried by fiber increases which generates nonlinear effect such as SPM, XPM, SRS, SBS and FWM. Four wave mixing (FWM) is one of the most troubling issues. The FWM gives crosstalk in DWDM system whose channel spacing is narrow. By using the fiber with proper amount of dispersion and by unequal spacing between channels it is possible to suppress FWM crosstalk. In this paper the effect of FWM on optical system is considered and different techniques are compared to suppress FWM. Also optical spectrum and eye diagrams are observed for various dispersion and equal or unequal spacing at attenuation 0.2 dB, power 0.2 mW and wavelength 1550 nm.