一种具有低折射率的高对比度光栅反射镜的设计

Design of High Contrast Grating Mirror with Low Index Grating Layer

设计并研究了一种工作于2μm波段的Ga Sb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2μm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/λ_0>9.5%,带宽中心波长为2.003μm,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1.1μm,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 Ga Sb 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 the2 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.