Opt Lett. 2018 Jul 15;43(14):3208-3211. doi: 10.1364/OL.43.003208.
Bragg filters stand as key building blocks of the silicon-on-insulator (SOI) photonics platform, allowing the implementation of advanced on-chip signal manipulation. However, achieving narrowband Bragg filters with large rejection levels is often hindered by fabrication constraints and imperfections. Here, we show that the combination of single-side corrugation asymmetry and subwavelength engineering provides a narrowband response with large corrugations, overcoming minimum feature size constraints of conventional Si Bragg filters. We comprehensively study the impact of the corrugation asymmetry in conventional and subwavelength single-etched SOI Bragg filters, showing their potential for bandwidth reduction. Finally, we experimentally demonstrate novel subwavelength geometry based on shifted corrugation teeth, achieving null-to-null bandwidths and rejections of 0.8 nm and 40 dB for the symmetric configuration and 0.6 nm and 15 dB for the asymmetric case.
布拉格滤波器是绝缘体上硅（SOI）光子学平台的关键组成部分，可实现先进的片上信号处理。然而，实现具有大抑制比的窄带布拉格滤波器通常受到制造限制和不完美的限制。在这里，我们表明单侧波纹不对称性和亚波长工程的结合提供了具有大波纹的窄带响应，克服了传统 Si 布拉格滤波器的最小特征尺寸限制。我们全面研究了传统和亚波长单刻蚀 SOI 布拉格滤波器中波纹不对称性的影响，展示了它们在带宽减小方面的潜力。最后，我们实验证明了基于偏移波纹齿的新型亚波长结构，对于对称结构，实现了零到零带宽和 40 dB 的抑制，对于非对称结构，实现了 0.6nm 和 15 dB 的抑制。
