In this paper, the sandwiched configuration is designed under normal incidence with zeroth order eliminated so as to design a highly-efficient four-port output with polarization independence. Through rigorous coupled-wave analysis method, the splitting parameters are calculated to get a good polarization-independence effect, where the four reflective efficiencies are over 20%, respectively. The final findings show that this grating has good diffraction characteristics and high stability in practice. Furthermore, the coupling mechanism of grating can be explained for the cancellation of the zeroth order by studying the overlap integral and the electric field distribution.

中文翻译：

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已取消零订单的覆盖式四端口反射分配器

在本文中，在垂直入射下设计了夹层配置，消除了零阶，从而设计了一个具有偏振无关的高效四端口输出。通过严格的耦合波分析方法，计算出分裂参数，获得了良好的偏振无关效果，其中四种反射效率分别超过20%。最终的研究结果表明，这种光栅在实际应用中具有良好的衍射特性和较高的稳定性。此外，通过研究重叠积分和电场分布，可以解释光栅的耦合机制用于消除零级。