Ultra fast pulse evolution in a semiconductor quantum well structure (QWS) is theoretically analyzed using split-step Fourier method. The induced polarization in the medium has been obtained using Semiconductor Bloch equations. The non-linear SchrÃ¶dinger equation is numerically solved by taking into account the induced polarization. So far, the pulse shape studies are based on the group velocity dispersion (GVD), third-order dispersion (TOD) and self phase modulation (SPM) effects. However, at high excitation intensity the group velocity also becomes intensity dependent. In the present analysis, the interplay of GVD, TOD and SPM leading to the change in pulse shape is studied giving due consideration to the intensity dependent group velocity of the medium. The result of numerical analysis made for a GaAs/AlGaAs QWS manifests significant influence of intensity dependent group velocity on the pulse shape.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.