A reflective dual-function pencil-like grating under second Bragg incidence is proposed in this paper. The finite element analysis method is chosen to be the research technique of this grating. Based on it, the influence of the incident angle, period, duty cycle, incident wavelength, and other parameters on the diffraction efficiency are analyzed in detail. At an incident laser wavelength of 1.55 μm, for TE polarization, the efficiency of −2nd order is 96.57% so that the proposed grating can be regarded as a single-port high-efficiency reflective grating. For TM polarization, the grating can function as a dual-port grating with the efficiency 46.03% for 0th order and 45.96% for −2nd order. What is more, the proposed grating has a broader angular bandwidth compared with other dual-function gratings, which ensures the diffraction performance of the grating while allowing some operational changes.

提出了一种在二次布拉格入射下具有反射性的双功能铅笔状光栅。选择有限元分析方法作为该光栅的研究技术。在此基础上，详细分析了入射角，周期，占空比，入射波长等参数对衍射效率的影响。在1.55的入射激光波长μm，对于TE偏振，-2阶的效率为96.57％，因此，所提出的光栅可被视为单端口高效反射光栅。对于TM偏振，该光栅可以用作双端口光栅，其0阶效率为46.03％，-2阶效率为45.96％。而且，与其他双功能光栅相比，所提出的光栅具有更宽的角度带宽，从而确保了光栅的衍射性能，同时允许一些操作上的变化。