This paper presents results of numerical modeling of a modified design of an optical sensor based on segmented periodic silicon oxynitride (SiON) grating evanescently coupled with silicon wire. This segmented grating works as a leaky waveguide, which filters input power from a broadband optical source and radiates it as an outcoming optical beam with both a small wavelength band and a small beam divergence. The radiation angle strongly depends on the refractive index of the grating environment and provides sensor interrogation by measuring the far field pattern in the focal plane of the lens, which is placed near the sensor element. The device concept was verified by direct numerical modeling through the finite difference time domain (FDTD) method and provided moderate intrinsic limit of detection (iLOD) 0.004 RIU with a possible iLOD 0.001 RIU for 10 mm-long structures.

中文翻译：

---

通过硅线波导上的二氧化硅缓冲器上的周期性光栅条辐射的远场图案进行光学传感的数值模拟。


本文介绍了基于分段周期氮氧化硅 (SiON) 光栅与硅线倏逝耦合的光学传感器改进设计的数值模拟结果。这种分段光栅充当漏波导，过滤来自宽带光源的输入功率，并将其作为具有小波长带和小光束发散度的输出光束辐射。辐射角很大程度上取决于光栅环境的折射率，并通过测量放置在传感器元件附近的透镜焦平面中的远场图案来提供传感器询问。该设备概念通过时域有限差分 (FDTD) 方法的直接数值建模进行了验证，并为 10 毫米长的结构提供了 0.004 RIU 的中等固有检测限 (iLOD)，以及可能的 iLOD 0.001 RIU。