This work is carried out to present the design study and simulation models for semiconductor laser manufacturing. The work presents a theoretical investigation of the band structure of semiconductor laser. The function of the density of states in energy band for different materials has been found, for GaAs g(E)=9.552×1020 (1\cm3) in conduction band and g(E)=4.65×1020 (1\cm3) in valence band. Also the position of the Fermi level and free carrier concentration of extrinsic semiconductors for both the donor and the accepter type with the affecting parameters has been found. The results are computed using computer program which is written in MATLAB 7. The results obtained are divided in to two parts; the experimental part contains studying the important parameters of semiconductor laser diode, which are the measurements of the output power and the laser beam divergence. While the second part presents the simulation model of semiconductor laser diode, the usage of GaAlAs as a suitable semiconductor material for a laser diode ( =852 nm). The basic process steps for GaAs wafer preparation are presented. The type of an edge emitting laser and its layers of the hetero-structure grown epitaxialy on GaAs substrate are proposed.