大功率半导体激光器腔面膜的场强分布优化

Optimization of Electric Field Intensity Distribution on High Power Semiconductor Laser Facet Film

为了提高半导体激光器腔面膜的激光损伤阈值,进而提高激光器输出功率,对激光器的灾变性光学镜面损伤产生的原因进行了探讨。根据损伤原理,将高反膜中场强最大处移出界面,采用光学传输矩阵,对厚度连续变化的界面场强和反射率进行了计算,得到优化高反膜系,优化膜系减小了界面处的光场对薄膜的损伤。采用改进后束流密度更大的LaB6作为阴极原位等离子源,对离子源清洗的参数进行了优化。薄膜制备前期使用离子清洗的方法在真空环境下对腔面进行去氧化,在制备过程中使用电子束蒸发离子源辅助沉积,并测试了薄膜在高温高湿环境下的稳定性。使用该优化的膜系和清洗方法制备的半导体激光器,在准连续输出时,功率由4.6 W提升到了7.02W,工作电流由5A提升到了8A。

In order to improve the damage threshold of semiconductor laser facet film and increase the laser output power, the causes of the catastrophic optical mirror damage in the laser are discussed. The highest field intensity in the high-reflective （HR） film is moved out of the interface in view of the damage principle. The reflectance and electric field distribution are simulated with film thickness changing continuously by using optical transmission matrix to get the optimized high reflective film, and the film damage is reduced at the interface by the optimized film. LaB6 with improved higher plasma density is adopted as in situ plasma source, and the cleaning parameter of ion source is optimized. In the earlier period of preparing film, facet deoxidation is made with ion pre-cleaning in vacuum environment, and the film is fabricated with ion-assisted electron beam evaporation, and the stability of the film is tested under high temperature and high humidity environment. The laser output power is raised from 4. 5 W to 7.02 W, operating current is raised from 5 A to 8 A in the case of the quasi-continuous operation with the optimized film and cleaning method.