Parameter extraction of semiconductor optical amplifier was carried out using wideband steady-state numerical model and the Levenberg-Marquardt method. An amplified spontaneous emission (ASE) spectrum and signal gain versus bias characteristic measurements and Levenberg-Marquardt method was used to determine the material parameters of a homogeneous buried ridge stripe SOA. The SOA carrier density and total signal and ASE photon rates for a signal power above saturation were presented. The results show that the analysis of such spatial distributions can be used to aid SOA designs and optimization.