【作者】 王巧云；

【导师】 于清旭；

【作者基本信息】 大连理工大学 ， 光学工程， 2010， 博士

【摘要】 随着工业和科技的发展,适用于石油化工、流体工程、风洞实验、飞机发动机和机翼空气动力学测试、生物医学以及电力工业运行安全等领域静压以及动态压强的高性能测量技术显得尤为重要。基于非本征法布里-珀罗干涉仪(Extrinsic Fabry-Perot Interferometer, EFPI)结构的膜片式光纤EFPI传感器具有结构简单、本质安全、灵敏度高、频带宽、抗电磁干扰、耐高温等优点,特别适用于高温、强磁场干扰和易燃易爆等恶劣环境下对静态低压、微压和声波等物理量的测量。本文对膜片式光纤EFPI传感器的相关理论、器件和应用进行了深入的研究。论文的主要工作概括如下：在对膜片式光纤EFPI传感器相关理论研究的基础之上,设计并制作了具有压力平衡结构的全石英膜片式光纤EFPI低压传感器。采用一种锥形口双孔结构石英毛细管作为光纤EFPI传感器的光纤准直和支撑元件,选用厚度为30μm的石英膜片作为压力敏感元件,利用CO2激光热熔技术对石英膜片和毛细管进行密封连接。通气孔结构以及低热膨胀系数的石英材料使得膜片式光纤EFPI传感器具有较小的温度敏感性。结合基于最小均方误差估计的光纤EFPI传感器解调系统对膜片式光纤EFPI低压传感器的性能进行了测试。实验结果表明该系统的腔长变化分辨率为0.12nm,相应的压强分辨率为4.7Pa,在0-3KPa的压强范围内,传感器的灵敏度达到25.89nm/KPa,腔长与压强的线性相关系数为0.99958。首次采用新型的聚合物光子材料杂萘联苯型聚芳醚砜酮(poly, phthalazinone ether sulfone ketone, PPESK)材料作为膜片式光纤EFPI声波传感器的敏感膜片,结合工作点自稳定的干涉／强度解调方法,设计并研制了基于可调谐非相干光源和可调谐光纤激光器的工作点自稳定光纤声波传感器(光纤麦克风)系统,实现了空气声波信号的高灵敏度测量。对光纤麦克风的性能测试实验结果表明,对频率为1KHz的正弦声波信号,膜片式光纤EFPI声波传感器在0-3Pa的声压范围内具有良好的线性输出,线性相关系数为0.99979；信噪比为29dB;灵敏度达31mV/Pa。在频率为100Hz-10KHz范围内具有平坦的响应：-30.54±0.88dB (Re.1V/Pa)将膜片式光纤EFPI声波传感器用于光声光谱微量气体检测系统中的光声信号检测,可以实现微量气体光声探测器探头端无源,实现全光探测。针对共振式光声池的声学特性,设计并制作了基于有机聚合物材料PPESK材料的膜片式光纤EFPI声波传感器,该传感器的膜片有效直径为2.75mm,在200Hz-2500Hz的频率范围内具有较平坦的响应,灵敏度为-16.65±0.63 dB；在1KHz的信噪比为35dB。应用该光纤麦克风,结合共振式光声池、可调谐非相干光源(ASE)和光纤激光器,采用波长调制和二次谐波探测技术,对乙炔以及氨气进行了实验测量。在调制频率为802Hz,调制振幅为14mV的条件下选用波长为1530.37nm的P9峰对乙炔气体进行了测量：在0.05-1ppm浓度范围内,光声信号与乙炔气体浓度具有很好的线性关系,其线性相关系数为0.99981。在常温常压下,对浓度为50ppb的流动状态乙炔气体所测量得到的二次谐波信号的信噪比为32dB,相应的乙炔的检测极限灵敏度为1.56ppb。在调制频率为818Hz,调制振幅为14mV的情况下选用波长为1531.7nm的吸收波长对氨气进行了测量：在0.3-2ppm氨气浓度范围内,光声信号与氨气浓度线性相关系数为0.99976；浓度为500ppb的流动的氨气所测量得到的二次谐波信号的信噪比为48dB,对氨气的检测极限灵敏度为10.4ppb。该系统在医学呼吸气体监测和诊断、在电力系统大型变压器局部放电监测等领域有广阔的应用前景。更多还原

【Abstract】 As the development of the industry and technology, high-performance measurements on static and dynamic pressure have becoming more and more important in many industrial areas, such as petrochemical industry, fluid engineering, wind tunnel test, biomedicine and industrial safety, etc. Because of the advantages of compact size, high sensitivity, high frequency response and immunity to electromagnetic interference, diaphragm-based extrinsic Fabry-Perot Interferometer (EFPI) optical fiber sensor is a good choice to detect the low pressure and acoustic wave in harsh environment with high temperature and strong electromagnetic interference. In this dissertation, systematic and intensively study on the theory, devices and applications of the diaphragm-based EFPI optical fiber sensor is presented. The major research works are outlined as followings:Based on the theoretical study of the diaphragm-based EFPI optical fiber sensor, an all silica diaphragm-based EFPI optical fiber differential pressure sensor with the pressure balance structure is designed. A capillary with cone-shaped cup and two holes is employed as the alignment and support component of the diaphragm-based EFPI optical fiber sensor, which use a silica diaphragm with 30μm thickness as sensing element. The silica diaphragm is bonded with the capillary by carbon dioxide laser. Due to the vent structure and the low thermal expansion coefficient of the silica material, this sensor has low temperature response and high sensitivity. The demodulation algorithm based on the minimum mean square error estimation is used. Experimental results show that the resolution of this system is 0.12nm, corresponding to a pressure resolution of 4.7Pa. The sensitivity is 25.89nm/KPa in the range of 0-3KPa with a linear correlation coefficient of 0.99958.The novel polymer poly(phthalazinone ether sulfone ketone, PPESK) diaphragm is used as the sensing element of diaphragm-based EFPI fiber optical acoustic sensor for the first time. The self-stabilized quadrature point of optical acoustic sensor (optical microphone) interferometer/intensity systems based on tunable incoherent light source and a tunable fiber laser are designed and studied in this thesis. Based on this self-stabilized system, the polymer diaphragm-based EFPI fiber acoustic sensor can be used to detect the acoustic wave in air with high sensitivity. Experimental results show that the fiber acoustic sensor has a linear response in the range of 0-3Pa at 1 KHz with linear correlation coefficient of 0.99979. The sensitivity of fiber acoustic sensor is 31mV/Pa and its signal-to-noise ratio is 29dB. This sensor can be used for acoustic measurements in a frequency range from 100 Hz to 12.7 KHz and the sensitivity is-30.54±0.88dB (Re.1V/Pa) corresponding to this frequency range. The photoacoustic spectroscopy trace gas detection system based on the PPESK diaphragm EFPI fiber acoustic sensor are designed and studied based on the acoustic characteristics of the resonant photo-acoustic cell. This system is passive and can realize all-optical detection. The diameter of the PPESK diaphragm is 2.75mm. The sensor has a flat response in a range of 200Hz to 2500Hz with a sensitivity of -16.65±0.63dB and the signal-to-noise is 35dB at 1KHz. Using wavelength modulation and second harmonic detection method, the acetylene and ammonia are chosen for the demonstration of this photoacoustic spectroscopy system. The acetylene was detected at the absorption peak of 1530.37nm with the modulation frequency of 802Hz and modulation amplitude of 14mV. The linear relationship between the photoacoustic signal and the acetylene concentration in a range of 0.05ppm to lppm is obtained and the linear correlation coefficient is 0.99981. The signal-to-noise of acetylene absorption spectrum for 50ppb concentration is 32dB and the detection limit is 1.56ppb. The ammonia was detected at an absorption peak of 1531.7nm with the modulation frequency as 818Hz and modulation amplitude of 14mV respectively. Experimental results demonstrate that there is a linear relationship between the photo-acoustic signal and the ammonia in a range from 0.3ppm to 2ppm and its linear correlation coefficient is 0.99976. The signal-to-noise of ammonia absorption spectrum for 500ppb concentration is 48dB and the detection limit is 10.4ppb. This system would have great potential applications in biomedicine and safety monitoring of electric power systems, etc.更多还原