为实现2 μm低发散角激光，提出在GaSb基半导体激光器中引入布拉格反射波导，利用光子带隙效应替代传统的全反射进行光场限制。研究了分布反馈反射镜(DBR)的厚度、对数、高低折射率DBR厚度比以及中心腔厚度等参数对激光器垂直远场发散角和光限制因子的影响。结果表明：垂直远场发散角随单对DBR厚度的增加而减小；光限制因子与远场发散角都随拉格反射镜对数的增加而减小，随高低折射率DBR厚度比的减小而增大；随着中心层厚度的增大，光限制因子减小而远场发散角增大。最终在理论上优化设计出了一种双边布拉格反射波导结构的超低垂直发散角2 μm GaSb基边发射半导体激光器，其垂直远场发散角可降低到10°以下。

The GaSb based Bragg reflection waveguide (BRW) lasers emitting at 2 μm with ultralow divergence were modeled. The dependence of far-field (FF) on the thickness of Bragg reflector and centre layer, the composition of Bragg reflector were simulated. The corresponding optical confinement factors were calculated. It was found that the increasing of the thickness of Bragg reflector and the thickness of high index material would improve the FF divergence. Thick center layer means the high OCF and FF angle, especially for the low thickness ratio between high index and low index material. Finally, the 2 μm GaSb based BRW lasers with an ultra-low vertical divergent FF angle less than 10° was optimized.