The Facet Passivation Characteristic of 940nm Semiconductor Laser

A novel facet coating technology is presented by studying catastrophic optical mirror damage mechanism of semiconductor laser. In this technology, semiconductor laser are cleaved in the air, and the surface oxide layer is removed with a low energy ion source, immediately flowed by coating the facet with 20nm of thin ZnSe passivation layer. The function of the passivation layer is to protect semiconductor laser facet, and prevent impurity particles diffusing to the facet. Finally the facet is coated with oxidative optical film. The test results of semiconductor laser output power show that output power with the coated ZnSe passivation layer method is 12% higher than coated Si passivation layer, and 36% higher than that coated oxidative optical film. The device coated oxidative optical film is failed when current is 4.1A, and the device coated with Si passivation layer is failed when current is 4.8A, the final failed of the device is coated ZnSe passivation layer. In conclusion, the method of coated ZnSe passivation layer on the semiconductor laser facet can effectively prevent the catastrophic optical mirror damage, and increase the output power of semiconductor lasers.