设计并研究了一种工作于2 μm波段的GaSb基亚波长高对比度光栅反射镜, 其具有低折射率光栅层结构。通过严格耦合波理论优化结构, 以最大限度地满足VCSEL腔面反射镜对反射率带宽的要求。反射镜对2 μm波段的TM模式具有优良的反射效率, 带宽与设计波长之比达15%(反射率R>99%), 在反射率R>99.9%的部分Δλ/λ0>9.5%, 带宽中心波长为2.003 μm, 与此同时TE模的反射率不超过70.20%。该反射镜结构中几个参数的制作容差较大, 且厚度低于1.1 μm, 有利于在垂直腔面发射半导体激光器上的单片集成。

A 2 μm subwavelength high contrast grating(HCG) mirror based on GaSb was designed and investigated, which had a low index grating layer structure. These designs of structure were optimized by use of rigorous coupled wave theory to maximize the reflectivity and bandwidth to meet the requirements of a VCSEL cavity mirror. The mirror has excellent reflectivity for TM mode of the 2 μm wave band. The ratio of bandwidth to design wavelength is 15%(reflectivity R>99%). When the reflectivity R>99.9%, Δλ/λ0>9.5%, and the bandwidth center wavelength is 2.003 μm. At the same time, the reflectivity of TE mode does not exceed 70.20%. Several parameters in the mirror structure have larger fabrication tolerances, and the thickness is less than 1.1 μm, which is beneficial to the monolithic integration on vertical cavity surface emitting semiconductor lasers.