【作者】 吴宇；

【导师】 杨国光；

【作者基本信息】 浙江大学 ， 测试计量技术及仪器， 2008， 博士

【摘要】 本文提出了一种基于微纳光纤环形谐振腔的MOEMS加速度传感器结构。微纳光纤是一种介观量级的光波导线结构,它既不同于普通光纤,也不同于集成光波导,这种微纳光纤是利用大比例的倏逝波传输,具有高色散区、强倏逝波耦合、低弯曲损耗等特性。利用微纳光纤所制作的光学器件,在一定程度上既解决普通光纤制作的光学器件尺寸很难缩小的问题,同时又能弥补集成光波导器件制作难度高和损耗较大的缺点和不足,并且微纳光纤的制作过程相对于集成光波导的制作工艺更为简单可行。而由这种微纳光纤构成的环形谐振腔具有低损耗、品质因素高的特点,因此微纳光纤环形谐振腔可以作为一种高灵敏度的光学传感器件。微纳光纤环与硅MEMS传感结构相结合的MOEMS加速度传感器是一种体积小、重量轻、功耗低、灵敏度高、动态范围大的加速度传感器。本文的主要研究内容包括以下几个方面:1、对加速度传感器的测量原理,发展历史和主要分类作了简要介绍。并结合MEMS和MOEMS的概念,分析了目前一些典型的MEMS和MOEMS加速度传感器的工作原理及各自的优缺点。提出了本文的主要研究内容、研究目标以及主要创新点。2、详细介绍了亚微米直径微纳光纤的传输理论和制作方法,并分析了微纳光纤的物理特性。深入研究了由微纳光纤构成的环形谐振腔的传输特性,以及影响谐振腔Q值的主要因素。3、结合微纳光纤环形谐振腔高Q值、高灵敏度的特点,我们首次提出了一种将微纳光纤环形谐振腔与硅MEMS传感结构相结合的加速度传感理论,并建立了基于该MOEMS加速度传感结构的数学模型,分析了其探测灵敏度和动态范围,并根据该传感结构的输出特性,提出了信号检测的方法。4、围绕硅MEMS加速度传感结构的参数设计、有限元仿真、制作工艺等展开详细研究,确定了该MEMS传感结构的几何参数、制作方法以及工艺流程,最后通过双面环氧树脂聚合物保护的深度体硅湿法刻蚀工艺完成该MEMS传感结构的制作。5、结合该MOEMS传感器的结构特点,我们构建了微纳光纤环与MEMS传感结构相粘接的微操作装置,并详细介绍了MOEMS加速度传感器的制作过程。通过实验对制作完成的MOEMS加速度传感器的输出光谱特性,模拟高g值的光谱检测、低频动态响应特性、重力场翻转输出光强的灵敏度检测以及温度效应进行了测试,测试结果表明我们制作的MOEMS加速度传感器采用光谱检测的方式可以实现超过30g大动态范围的测量,重力场翻转实验中输出光强的探测灵敏度为624.7mV/g,为普通商用MEMS加速度传感器实际输出灵敏度的6～10倍。而相关研究表明微光纤环形谐振腔的Q值还有较大的提升空间,随着微光纤环Q值的提高(从目前10~3增加到10~6),该MOEMS加速度传感器的探测灵敏度还将大幅提升。文章最后对本文所涉及的研究工作进行了总结,并对未来的主要工作方向提出了展望。更多还原

【Abstract】 This dissertation presents a novel MOEMS (Micro-Optical Electronical Mechanical System) accelerometer based on microfiber loop resonantor. Microfiber is a new type of waveguide wires with the diameters on the micro, even nanometer scale, and the characteristics of this microfiber are different from both conventional optical fibers and integrated optical waveguide structures. The microfiber loop resonantor, which is coupling by optical evanescent wave in the coupling region, and has shown the low-loss and high Q factor, so this resonator can be used for high sensitivity optical sensor devices. Moreover, the MOEMS accelerometer which combines microfiber technology with silicon MEMS (Micro-ElectroMechanical System) technology is presented in this dissertation.At the beginning of this dissertation, we introduced the background of this subject, and made a comparison with various kinds of MEMS and MOEMS accelerometers. The research object、main contents and novel ideas of this work were also introduced.As the microfiber is an important part of this MOEMS accelerometer. we analysed the principle of the transmission and physical characteristics of the microfiber, which is essential for the microfiber fabrication and application. The research of the mirofiber loop resonantor demonstrated that the Q-factor of microresonantors created by microfibers could potentially compete with the extremely high-Q and much low-loss whispering gallery mode microcavities.As the microfiber loop resonantor can be used for high sensitivity optical sensor devices, we designed a novel MOEMS accelerometer which based on this microfiber loop resonantor and silicon MEMS structure. We provided the sensing process and mathematical mode of this device, and analyzed its performances as well as the signal detecting methods.We also made much effort to the fabrication of the MEMS sensing structure. Firstly, we designed the geometry parameters of the MEMS structure. Secondly, we made the FEA (Finite Element Analysis) analysis of the design by ANSYS. At last, the MEMS acceleration sensing structure was designed, and fabricated by double-faced KOH anisotropic etching with epoxy polymer protecting.After the MEMS structure fabrication, we cemented the microfiber loop resonantor under a microscopical manipulation system, and tested the performances of this MOEMS accelerometer with the transmission spectrum in high-g driving, optical intensity sensitivity in gravity field, dynamic response and temperature effect. The test results demonstrated that this MOEMS accelerometer could support more than 30g acceleration load and its static optical intensity sensitivity is about 624.7mV/g, which is related to Q-factor of the microfiber loop resonantor and MEMS structure parameters. Along with the improvement of Q-factor from 10~3 to 10~6 in the future, the MEMS structure parameters would be optimized through experiments, this MOEMS accelerometer could achieve thousandfold intensity of detecting sensitivity.更多还原