设计了一种具有波长和偏振模式选择特性的GaAs材料的亚波长抗反射光栅，工作波长为976 nm。采用等效介质理论与薄膜理论对光栅进行初步设计，基于严格耦合波法依次对光栅占空比、脊高和周期进行优化确定，同时分析了各个参数对光栅透射率的影响。所设计的抗反射光栅分别具有99.99%（横电模）和99.86%（横磁模）的高透射率，并且在976 nm± 30 nm的范围内保持99%以上的高透射率，满足器件应用要求。最后研究了工艺误差导致的光栅非矩形形貌对光栅透射率以及偏振优势模式的影响。

A subwavelength anti-reflective grating made from GaAs material is proposed, with optional wavelength and polarization mode and a working wavelength of 976 nm. On the basis of effective medium theory and membrane theory, the grating is initially designed. Parameters of duty cycle, ridge height and period of the grating are optimized and determined according to the rigorous coupled wave theory. Meanwhile, the influence of various parameters on the grating transmissivity is analyzed. The designed anti-reflective grating is of high transmissivity, 99.99% for TE mode and 99.86% for TM mode, respectively. In the range of 976 nm± 30 nm, the transmissivity is above 99% for both mode gratings, which meets the requirements of device application. The effect of non-rectangular shape of the grating caused by fabrication error on the transmissivity and dominant polarization mode is studied.