P.C.T. Munaweera, K A I L Wijewardena Gamalath, Simulation of Pulse Propagation in Optical Fibers, ILCPA Volume 64, International Letters of Chemistry, Physics and Astronomy (Volume 64) https://www.scipress.com/ILCPA.64.159 Abstract: A theoretical model was developed for light pulses propagating in optical fibers by considering the nonlinear effects, the self-phase modulation and group velocity dispersion effects. The split step Fourier method was used to generate soliton pulses in a fiber composed of a glass core surrounded by a cladding layer. Gaussian and hyperbolic secant input pulses were used for the simulation. By varying the initial chirp, input power and nonlinear coefficient for an input Gaussian pulse at wavelength of λ =1.55μm with initial pulse width 125ps for second order dispersion β<sub>2</sub>=−20 ps<sup>2</sup> km<sup>-1</sup> , nonlinear parameter γ=3W<sup>-1</sup>kg<sup>-1</sup> and initial chirp C=−0.25 two near soliton pulses were generated for input powers P = 0.54mW and P = 0.64mW and a perfect soliton for the hyperbolic secant input pulse. Keywords: Gaussian Pulse, Group Velocity Dispersion, Hyperbolic Secant Pulse, Optical Fibers, Self-Phase Modulation, Soliton, Split Step Fourier Method