Pérez-Galacho Diego, Alonso-Ramos Carlos, Mazeas Florent, Le Roux Xavier, Oser Dorian, Zhang Weiwei, Marris-Morini Delphine, Labonté Laurent, Tanzilli Sébastien, Cassan Éric, Vivien Laurent
Opt Lett. 2017 Apr 15;42(8):1468-1471. doi: 10.1364/OL.42.001468.
The high index contrast of the silicon-on-insulator (SOI) platform allows the realization of ultra-compact photonic circuits. However, this high contrast hinders the implementation of narrow-band Bragg filters. These typically require corrugation widths of a few nanometers or double-etch geometries, hampering device fabrication. Here we report, for the first time, to the best of our knowledge, on the realization of SOI Bragg filters based on sub-wavelength index engineering in a differential corrugation width configuration. The proposed double periodicity structure allows narrow-band rejection with a single etch step and relaxed width constraints. Based on this concept, we experimentally demonstrate a single-etch, 220 nm thick, Si Bragg filter featuring a corrugation width of 150 nm, a rejection bandwidth of 1.1 nm, and an extinction ratio exceeding 40 dB. This represents a 10-fold width increase, compared to conventional single-periodicity, single-etch counterparts with similar bandwidths.
绝缘体上硅（SOI）平台的高折射率对比度使得超紧凑光子电路的实现成为可能。然而，这种高对比度阻碍了窄带布拉格滤波器的实现。这些滤波器通常需要几纳米的波纹宽度或双蚀刻几何结构，这会妨碍器件制造。据我们所知，在此我们首次报告了基于差分波纹宽度配置中的亚波长折射率工程实现的SOI布拉格滤波器。所提出的双周期性结构允许通过单次蚀刻步骤实现窄带抑制，并放宽宽度限制。基于这一概念，我们通过实验展示了一种单次蚀刻、厚度为220 nm的硅布拉格滤波器，其波纹宽度为150 nm，抑制带宽为1.1 nm，消光比超过40 dB。与具有相似带宽的传统单周期、单次蚀刻同类器件相比，这代表着宽度增加了10倍。
