表面光栅垂直腔面发射激光器偏振特性研究

研究了表面光栅结构对垂直腔面发射激光器(VCSEL)的偏振控制作用。引入表面光栅后，对不同刻蚀深度下的偏振相关的镜面损耗进行了仿真，结果表明表面光栅刻蚀深度在44~130 nm范围内均可实现稳定偏振，具有较大的工艺容差。表面光栅VCSEL在基横模工作状态下偏振抑制比(Orthogonal Polarization Suppression Ratio, OPSR)超过20 dB，偏振光谱峰间偏振抑制比达到40 dB，且在多横模状态也实现了有效的偏振控制。为了进一步验证光栅对偏振控制的效果，制作了方向互相垂直的两种表面光栅，具有这两种方向光栅的VCSEL的OPSR均达20 dB以上。测试分析表明表面光栅是VCSEL实现稳定偏振的一种有效手段。

Polarization characteristics of surface grating vertical cavity surface emitting laser

The polarization control of vertical cavity surface emitting laser (VCSEL) with surface grating structure was studied. After introducing the surface grating, the polarization-dependent mirror loss under different etching depths was simulated. The results show that the etching depth of the surface grating can achieve stable polarization in the range of 44 nm to 130 nm, which has a large fabrication tolerance. For the fundamental transverse mode, the orthogonal polarization suppression ratio (OPSR) of the surface grating VCSEL is more than 20 dB, and the peak-to-peak OPSR of the polarization-resolved spectrum reaches 40 dB. Effective polarization control can also be achieved even for multimode VCSEL. In order to further verify the effect of the grating on polarization control, two surface gratings with mutually perpendicular directions were fabricated. The OPSRs of the VCSEL with the two directional gratings were more than 20 dB. The test results show that surface grating is an effective means for VCSEL to achieve stable polarization.