Bragg gratings are fundamental building blocks for integrated photonic circuits. In the high-index contrast silicon-on-insulator material platform, it is challenging to accurately control the grating strength and achieve narrow spectral bandwidths. Here we demonstrate a novel Bragg grating geometry utilizing a silicon subwavelength grating (SWG) waveguide with evanescently coupled periodic Bragg loading segments placed outside the SWG core. We report experimental 3 dB filter bandwidths in a range from 8 nm to 150 pm by adjusting the distance of the Bragg loading segments from the core and the relative phase shift of the segments on the two sides of the waveguide, with a structure that has a minimum feature size of 100 nm.

中文翻译：

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亚波长光栅超材料波导中的布拉格滤波器带宽工程

布拉格光栅是集成光子电路的基本构建块。在高折射率对比绝缘体上硅材料平台中，准确控制光栅强度并实现窄光谱带宽是一项挑战。在这里，我们展示了一种新颖的布拉格光栅几何形状，该几何形状利用硅亚波长光栅（SWG）波导以及e逝耦合的周期性布拉格载荷段放置在SWG核芯之外。我们通过调整布拉格负载段距纤芯的距离以及波导两侧的段的相对相移，报告了在8 nm至150 pm范围内的实验性3 dB滤波器带宽。最小特征尺寸为100 nm。