An optical pulse compressor is investigated over a large range of compression factors, fiber lengths and laser powers. The given theory for zero group velocity dispersion is valid over the investigated range of grating-prism distances. The influence of stimulated Raman scattering limited the feasible compression factors due to instabilities of the output pulse. For long fiber lengths it is experimentally shown that group velocity dispersion is present while the theory of zero group velocity dispersion still predicts the right pulse duration. The advantage of the presence of group velocity dispersion is the improved beam quality. The optical pulse compressor investigated uses a mode-locked Nd:YLF laser followed by an adjustable fiber-grating compressor stage.