针对当前2.0 μm GaSb基垂直腔面发射激光器发展中由于传统的P面分布布拉格反射镜(P-DBRs)带来的高电阻和严重光吸收这一瓶颈问题, 采用严格耦合波方法仿真设计了含高对比度亚波长光栅(HCG)的P面反射镜.实验结果表明, 这种制备工艺简单的反射镜在2.0 μm 中心波长附近, TM波入射时反射率超过99.5%的高反射带宽为278 nm, 反射率99.9%以上的高反射带宽达到148 nm, 完全能够满足VCSEL对谐振腔镜的要求, 且能有效避免因异质外延等造成反射镜衍射特性劣化等问题.

The high resistance and severe optical absorption brought by the traditional P-side distributed Bragg reflectors (P-DBRs) have been the bottleneck of the development of 2.0 μm GaSb based vertical cavity surface emitting lasers (VCSELs). For this reason, a P-side mirror with high contrast subwavelength grating (HCG) is designed and simulated by the rigorous coupled wave analysis method. The testing results show the HCGmirror,easy to make, has 278nm bandwidth with reflectivity more than 99.5% and 148 nm bandwidth with reflectivity greater than 99.9% around the central wavelength of 20 μm for TM mode. Such a mirror can fully meet the requirements of VCSELs, and can effectively avoid the problem of diffraction characteristics deterioration caused by heteroepitaxy and so on.