Appl Opt. 2021 Sep 1;60(25):7828-7833. doi: 10.1364/AO.434927.
Designing reliable and compact integrated biosensors with high sensitivity is crucial for lab-on-a-chip applications. We present a bandpass optical filter, as a label-free biosensor, based on a hybrid slot waveguide on the silicon-on-insulator platform. The designed hybrid waveguide consists of a narrow silicon strip, a gap, and a metallic Bragg grating with a phase-shifted cavity. The hybrid waveguide is coupled to a conventional silicon strip waveguide with a taper. The effect of geometrical parameters on the performance of the filter is investigated by 3D finite-difference time-domain simulations. The proposed hybrid waveguide has potential for sensing applications since the optical field is pulled into the gap and outside of the silicon core, thus increasing the modal overlap with the sensing region. This biosensor offers a sensitivity of 270 nm/RIU, while it only occupies a compact footprint of 1.03µ×17.6µ.
设计具有高灵敏度的可靠、紧凑的集成生物传感器对于芯片实验室应用至关重要。我们提出了一种基于绝缘体上硅平台的带通光滤波器，作为无标记生物传感器。设计的混合波导由一个狭窄的硅条、一个间隙和一个带有相移腔的金属布拉格光栅组成。混合波导通过锥形与传统的硅条波导耦合。通过三维有限差分时域模拟研究了几何参数对滤波器性能的影响。由于光场被拉进间隙并移出硅芯，从而增加了与传感区域的模式重叠，因此这种混合波导具有传感应用的潜力。该生物传感器的灵敏度为 270nm/RIU，而其占地面积仅为 1.03µ×17.6µ。
