基于Fabry-Perot干涉仪的微型光纤声压传感器关键技术研究

发布时间：2018-03-18 04:10

本文选题：Fabry-Perot　切入点：光纤　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：光纤声压传感系统的发展对声压传感器提出了小型化的要求。受探测原理制约,传统的长臂长型光纤声压器在小型化方向遇到困难;而将MEMS技术同非本征型Fabry-Perot传感技术结合组成新型光纤干涉传感器有望突破该瓶颈。目前该技术正处于起步阶段,面临诸多问题,如长期忽视声压传感探头结构设计的理论分析;缺乏低成本、高性能声压敏感元件的加工方法;在水声探测中无法同时兼顾抗静水压和高灵敏度等。本论文针对微型EFPI光纤声压传感器中的若干关键技术开展相关研究,主要完成了如下工作:1.完善了EFPI光纤声压传感器的理论分析模型。分别从光学、机械和声学三个方面对传感器进行理论分析。在光学分析中,对光纤出射光束的传输特性和耦合特性进行了理论分析,利用实验验证了高斯模式耦合模型的合理性,并详细分析了倾斜和错位损耗对干涉条纹的影响;在机械性能分析中,从膜片的振动方程详细推导了膜片的振幅分布,得到了平板模型和薄膜模型的解析表达式,并针对引入波纹结构之后的膜片结构机械性能进行了分析;在声学分析中,对声压传感器建立了等效电路模型,分析了各组成部分的声阻抗表达式,并详细讨论了膜片性质、工作环境、传感器结构参数等对传感器声学性能的影响,为声压传感器的结构设计提供理论指导。2.提出了基于牺牲层的高质量金属膜片干法转移加工工艺。采用易溶于丙酮溶液的低成本正性光刻胶做牺牲层,利用磁控溅射在牺牲层表面加工金属薄膜,最后进行干法贴合转移,利用膜片中残留的内应力有效减少膜片的皱褶。实验结果表明,加工得到的金属银薄膜在直径达到2.5 mm时其表面起伏小于14?m。通过在薄膜中引入波纹结构,解决了薄膜加工中内应力较高且难以控制的问题,并第一次制作了基于金属银纹膜结构的EFPI光纤声压传感器。测试结果表明,基于银纹膜的声压传感器灵敏度比相同条件下平膜传感器的灵敏度提高了约1倍。3.设计加工了多种EFPI光纤声压传感器结构。利用金属银膜分别加工得到短腔长同轴型平膜/纹膜光纤麦克风、短腔长垂直轴型平膜光纤麦克风、长腔长同轴型平膜光纤麦克风等。利用金属银膜和PET膜片分别加工得到微型光纤水听器;其中利用空气作为F-P腔填充物实现水听器的高灵敏度检测,利用大体积的微流路结构实现水听器的抗静水压性能。对加工得到的光纤声压传感器的待测参数进行了讨论,利用ASE光源、DFB光源分别搭建了强度解调装置,利用EDFL光源搭建了基于PGC-DCM算法的相位解调装置,并对加工得到的四种光纤麦克风和两种光纤水听器的性能进行了详细的测试与分析。
[Abstract]:The development of optical fiber sound pressure sensing system requires the sound pressure sensor to be miniaturized. The combination of MEMS technology and non-intrinsic Fabry-Perot sensor is expected to break through the bottleneck. At present, the technology is in its infancy, and it faces many problems, such as ignoring the theoretical analysis of sound pressure sensor structure design for a long time. There is a lack of low cost and high performance sound pressure sensor processing methods, and it is not possible to combine hydrostatic pressure and high sensitivity in underwater acoustic detection. In this paper, some key technologies in miniature EFPI fiber optic acoustic pressure sensor are studied. The main work is as follows: 1. The theoretical analysis model of EFPI optical fiber acoustic pressure sensor is perfected. The sensor is analyzed theoretically from three aspects: optics, mechanism and acoustics. The propagation and coupling characteristics of optical fiber outgoing beams are theoretically analyzed. The rationality of Gao Si mode coupling model is verified by experiments, and the effects of tilt and dislocation loss on interference fringes are analyzed in detail. From the vibration equation of the diaphragm, the amplitude distribution of the diaphragm is derived in detail, and the analytical expressions of the plate model and the film model are obtained, and the mechanical properties of the diaphragm structure after the introduction of corrugated structure are analyzed. The equivalent circuit model of sound pressure sensor is established, the expressions of acoustic impedance of each component are analyzed, and the effects of diaphragm properties, working environment and sensor structure parameters on the acoustic performance of the sensor are discussed in detail. To provide theoretical guidance for the structural design of sound pressure sensor. 2. A high quality metal film dry transfer process based on sacrificial layer is proposed. Low cost positive photoresist, which is easily soluble in acetone solution, is used as sacrificial layer. Metal film was fabricated by magnetron sputtering on the surface of sacrificial layer. Finally, dry bonding transfer was carried out, and the residual internal stress in the membrane was used to effectively reduce the wrinkle of the film. The experimental results show that, When the diameter is 2.5 mm, the surface fluctuation of the fabricated silver film is less than 14? By introducing corrugated structure into the film, the problem of high internal stress and difficult to control in thin film processing is solved, and the EFPI optical fiber acoustic pressure sensor based on metal silver film structure is fabricated for the first time. The test results show that, The sensitivity of the acoustic pressure sensor based on silver film is increased by 1 times than that of the flat film sensor under the same condition. Several EFPI fiber optic acoustic pressure sensor structures are designed and fabricated. The short cavity length and the same length are obtained by using metal silver film separately. Axial flat film / striated film optical fiber microphone, The short cavity long vertical axis flat film optical fiber microphone and the long cavity long coaxial flat film optical fiber microphone were fabricated by metal silver film and PET film respectively. Air is used as the filler of F-P cavity to realize the high sensitivity detection of hydrophone, and the hydrostatic resistance of hydrophone is realized by using large volume microfluidic structure. The parameters of the fiber optic acoustic pressure sensor are discussed. The intensity demodulation device is built with ASE light source and the phase demodulation device based on PGC-DCM algorithm with EDFL light source. The performances of four kinds of fiber optic microphones and two kinds of fiber optic hydrophones are tested and analyzed in detail.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TP212

【参考文献】