Si基双环级联光学谐振腔应变检测研究

绝缘衬底上的硅材料制备的光学微环谐振腔结构具有高灵敏度、结构尺寸小和极低模式体积等特性，被广泛应用到光信息传递、惯性导航领域，但极少被应用到力学信号的测试，为此，研究了一种基于硅基光学微环谐振腔结构的悬臂梁式应力/应变敏感计，利用微环谐振腔环形波导径向形变量作为感应应力的中间物理量，在外界应力作用下，环形波导的半径将发生改变，使结构的光学谐振参数产生变化，从而使光学微环谐振腔谐振谱线发生明显红移，体现出良好的应力/应变敏感特性;通过设计双环级联光学微腔，并采用MEMS光刻、ICP腐蚀工艺制备了嵌入式光学微腔应变计结构，结合理论计算了悬臂梁结构的应力应变敏感特性，经仿真及实验得到，应变计结构的应力/应变灵敏度分别为0.185 pm·kPa-1，18.04 pm·microstrain-1，与单环微腔结构相比，线性量程增加了近50.3%，应力灵敏度提高了近10.6%，初步验证了嵌入式光学微腔结构进行高灵敏度应力/应变检测的可行性，有望实现新型光学力敏传感器件的微型化、集成化。

Study on Strain Detection with Si Based on Bicyclic Cascade Optical Microring Resonator

Optical micro-ring resonator prepared on Silicon-On-Insulator (SOI) has high sensitivity, small size and low mode volume. Its high sensitivity has been widely applied to the optical information transmission and inertial navigation devices field, while it is rarely applied in the testing of Mechanics. This paper presents a cantilever stress/strain gauge with an optical micro-ring resonator. It is proposed the using of radius change of ring waveguide for the sensing element. When external stress is put on the structure, the radius of the SOI ring waveguide will be subjected to variation, which causes the optical resonant parameters to change. This ultimately leads to a red-shift of resonant spectrum, and shows the excellent characteristics of the structure’s stress/strain sensitivity. Designed a bicyclic cascade embedded optical micro-cavity structure, which was prepared by employing MEMS lithography and ICP etching process. The characteristic of stress/strain sensitivity was calculated theoretically. Two values of 0.185 pm·kPa-1 and 18.04 pm·microstrain-1 were obtained experimentally, which also was verified by theoretical simulations. Comparing with the single-loop micro-cavity structure, its measuring range and stress sensitivity increased by nearly 50.3%, 10.6%, respectively. This paper provides a new method to develop micro-opto-electromechanical system (MOEMS) sensors.