In this paper

the basic theory of frequency chirp in semiconductor lasers is discussed. The relation between linewidth broadening factor and semiconductor’s linewidth can be obtained by utilizing wave equations. The consistence between linewidth broadening factor and chirp parameter in optical fiber communication system is analyzed emphatically. Using Gaussian pulse as signal source

we study the effect of linewidth broadening factor and group velocity dispersion together on the performance of optical fiber communication system by solving nonlinear Schrdinger equation.