一种具有低折射率的高对比度光栅反射镜的设计

摘要

设计并研究了一种工作于2μm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/λ0>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 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. 003μm. At the same time, the reflectivity of TE mode does not exceed 70. 20％. Several parameters in the mir-ror structure have larger fabrication tolerances, and the thickness is less than 1. 1μm, which is ben-eficial to the monolithic integration on vertical cavity surface emitting semiconductor lasers.