The Preparation Of High-Power Semiconductor Laser Facet Coating

Reflectivity of cavity facets is about 32% for 808nm high power semiconductor lasers with <110> cleaving plane of GaAs crystal as resonant cavity. In order to gain high differential quantum efficiency, high output power and low threshold current, diode lasers should be facet coated with anti-reflective film in front cavity surface, and high reflective film in rear cavity surface.According to the principle of thin-film optics, we adopted Si and SiO₂ as coating materials, and designed the film structure. We studied facet coating technique by magnetron sputtering deposition equipment and obtained the optimized experiment condition by testing data analysis. Facet coating has been successfully prepared with front facet reflectivity of 6.87% and rear facet reflectivity of 97.83%. The prepared Si/SiO2 films are excellent in absorption, optical loss, reflectivity band width and simple for process. The reflectivity characteristic is tested by UV3100 spectrometer and test data, analysis are also given.