可见光波段双层浮雕型导模共振滤波器设计与分析

基于傅里叶模式理论分析了双层浮雕型导模共振光栅的共振效应，分别讨论了光栅的槽深、剩余厚度、周期以及填充系数对峰值反射率、带宽、旁带反射率的影响. 数据计算表明，欠刻蚀情形的误差宽容度远远优于过刻蚀情形，两者在光栅槽深相对误差小于15％的范围内，都能保证共振峰的衍射效率高于99.5%，在相同的误差范围内，共振峰线宽的相对误差将分别达到7％和60％，因此厚度误差集中反映在对共振线宽的改变上. 另外，光栅周期和填充系数的变化将明显改变共振峰中心波长和线宽. 关键词： 导模共振 平面波导 窄带滤波

Design and analysis of double layer resonant grating filters in the visible spectral region

Guide-mode resonances of double-layer gratings are analyzed with the Fourier modal method and the relationship between spectral characteristics of resonant gratings such as peak diffraction efficiency, linewidth and side-band reflectance and depth, period and fill ratio of grating are illustrated in detail. It is shown that the diffraction efficiency of resonant gratings will be higher than 99.5 percent when the groove depth tolerance is in the range of 15 percent, and mean while the relative error of line width will reach to 7 and 60 percent respectively for the negative and positive conditions. Compared with the position of resonant wavelength, the line width of resonant grating filters is relatively sensitive to the error of groove depth and residual thickness of waveguide layer when they deviate from designed values. Moveover, the resonant wavelength and width of spectrum do vary as a function of period and fill ratio.