A narrowband retroreflector consisting of a grating coupler and a waveguide cavity integrated on a highly reflective substrate is proposed. A theoretical model based on coupled-mode theories is discussed to provide analytical expression of the reflection and transmission coefficients under oblique incidence. The retroreflector was designed with a 20-µm aperture for 1540-nm-wavelength operation and 8-deg-angle incidence. Finite-difference time-domain simulation showed a retroreflection spectrum with a bandwidth of 2 nm and a maximum retroreflectance of 85% and a minimum specular reflectance of 5%.

中文翻译：

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基于导模谐振的窄带后向反射器设计。

提出了一种窄带回射器，它由光栅耦合器和集成在高反射衬底上的波导腔组成。讨论了基于耦合模式理论的理论模型，以提供斜入射下反射和透射系数的解析表达式。逆向反射器的孔径设计为20μm，可用于1540nm波长的操作和8度角入射。时域有限差分模拟显示的逆向反射光谱的带宽为2 nm，最大逆向反射率为85％，最小镜面反射率为5％。