Analysis of XPM effect with SPM and GVD in WDM fiber optic transmission system

Increased channel capacity of optical transmission system is obtained either by increasing the bit rate of transmission or by using the technique of wavelength division multiplexing (WDM). In long distance communication, higher launched power is required to achieve the required signal to noise ratio. But with the increased launched optical powers, bit rates and the number of wavelength channels, the nonlinear optical effects have been increased. Also, at high bit rate, group velocity dispersion (GVD) limits the transmission distance. Cross-phase modulation (XPM) is an important nonlinear impairment that causes interference through intensity-dependent phase shifts between two optical fields in optical networks using WDM. This effect limits the allowable input optical power and system capacity. The XPM effect with SPM and GVD degrade the system performances significantly. In this research work, a detail analysis have been done to find the mathematical expression for pulse broadening factor by solving nonlinear Schrödinger equation (NLSE) considering the effects of XPM with SPM and GVD in WDM system. By using this mathematical expression, pulse broadening factor has been visualized. The results are evaluated at different bit rates, different input power and varying transmission distance.