The effects of cross-phase modulation and third order dispersion on pulses and pulse broadening factor in the WDM transmission system

With the development of fiber communication, the emergence of large capacity, high bit-rate, high input optical power, and multi-channel in the wavelength division multiplexing(WDM) fiber optic transmission systems, the nonlinear cross-phase modulation (XPM) effect and the high order dispersions should be considered because these effects are inevitable and strong enough. When two optical pulses are incident at the input and propagate through the non-linear fiber, they interact with each other and overlap inside the medium through the XPM effect. The third order dispersion is an important limiting transmission factor. It is determinant on the pulse shape, pulse amplitude, pulse broadening and consequently in inter-symbol interference. The XPM-induced interaction can affect the pulse shape and spectra of two co-propagating optical pulses in the presence of third order group velocity dispersion. In this research work, a numerical analysis and simulation of the nonlinear Schrodinger equation (NLSE), which includes the contributions of XPM and third order dispersion, have been done by split step Fourier transform and MATLAB. Then the output pulse and pulse broadening factor have been visualized to investigate the combined effect of XPM and third order group velocity dispersion on pulse and pulse broadening factor. The results are analyzed and evaluated at different data rates and different input powers to control the spectrum of an optical pulse.