设计了具有双峰滤波特性的相移光栅及取样光栅,利用传输矩阵方法对其滤波特性进行了研究。结果表明,多π相移光栅及π相移取样光栅均可获得双峰滤波特性,并且π相移取样光栅比多π相移光栅具有更好的双峰滤波特性,其反射频谱的旁峰幅度比多π相移光栅低得多。调整π相移取样光栅的占空比(取样长度与取样周期的比值)位于0.66~0.8范围内时,得到了更好的双峰滤波特性,特别是占空比为0.75时其旁峰反射率整体上处于最低值。 The phase shift grating and sampling grating with bimodal filtering characteristics are designed and their filtering characteristics are studied by the transfer matrix method. The results show that the multi-π phase-shift grating and the π-phase-shift sampling grating both obtain the bimodal filtering characteristic, and the π-phase shifted sampling grating has better bimodal filtering characteristics than the multi-π phase-shifting grating. The peak amplitude of the reflection spectrum Much lower than the multi-π phase-shift grating. Adjusting the duty ratio of the π-shifted sampling grating (ratio of sampling length to sampling period) to be within the range of 0.66 to 0.8 gives better bimodal filtering characteristics, especially when the duty ratio is 0.75, Overall at the lowest value.