The Preparation Of High-Power Semiconductor Laser Cavity Face Film

This paper introduces the fundamental principle of semiconductor laser and its high-reflective coating which is deposited on the rear end face of resonant cavity. It also studies the design of film and the process of deposition.The single face reflectance of the optical resonant cavity which is composed of the mirrors formed from the natural cleavage GaAs face is only 32%. In order to improve the power of the laser, high reflectance film is coated on the rear face of the resonant cavity. Because the film must havelow absorption, low scatter and high threshold value, Al₂O₃, Si and SiO₂ are selected as the materials of the film by experiments. The reflectance has been increased using the design of the above three materials from 32% to above 97%. The cavity surface is also protected by the film. Moreover, the output power is increased and the service life is extended.The film is coated by Denton Integrity-36 vacuum deposition equipment associated with ion beam aid system. The spectrum curve is tested by spectrometer and the reflective layer structure is analysed by ellipsometer.