为了便于理解亚波长高折射率差光栅的谐振滤波机制，将光栅看作一个光学谐振器，用时域耦合模理论分析光栅滤波器的透射光谱，同时也验证了分析结果与严格耦合波算法仿真结果的一致性。在此基础上，分别分析入射角、光栅宽度以及温度对光栅滤波器的透射特性的影响及机理。研究结果表明通过改变入射角可以调控光栅滤波器透射光谱的线宽，而在小范围内改变光栅宽度和工作温度对透射光谱线宽没有影响。

Subwavelength high contrast grating (SHCG) is considered as an optical resonator for understanding its resonant filtering mechanism clearly. The transmission spectrum of SHCG is investigated by employing temporal coupled mode theory. The calculated result is in good agreement with the simulation obtained by using the rigorous coupled-wave analysis method. In addition，the influence and mechanism of the filter′s transmittance on incident angle，grating width and temperature are also investigated, respectively. The simulated results show that the spectrum linewidth of SHCG filter is mainly controlled by the incident angle. However, the spectrum linewidth is insensitive to the minor change of the grating width and the operating temperature.