光纤光栅法布里—珀罗传感系统光学增敏技术研究

发布时间：2018-09-07 08:53

【摘要】：光纤光栅法布里-珀罗(FBG-FP)传感系统因其结构简单、可靠性高等优点在光纤传感领域占有越来越重要的地位。光纤加速度计、光纤矢量水听器等光纤传感器由于尺寸和机械谐振的制约,不能从机械结构上实现小尺寸的高灵敏度传感。论文基于匹配干涉的光纤光栅法布里-珀罗腔传感系统,采用多次反射光脉冲提高传感光程的光学手段,实现了FBG-FP传感系统性能大幅度提升。论文主要创新点和成果如下:1.分析了FBG-FP光学增敏传感系统各个参数的优化设计方案,理论和实验研究了1~9阶匹配干涉的传感性能,验证了该系统具有提高FBG-FP传感系统灵敏度和分辨率水平的能力。2.提出了二次声光斩波、放大、滤波处理新技术,该技术解决了高倍增敏传感时存在的光功率衰落和不均衡问题,成功突破了常规FBG-FP光学增敏传感系统的增敏极限,将20倍增敏的本底噪声降低约11d B。3.提出了有源FBG-FP增敏传感新技术,该技术不仅能够解决高倍增敏时存在的光功率衰落和不均衡问题,而且具有更高的系统集成度和更低的成本。理论分析了有源FBG-FP的噪声性能和高阶脉冲均衡输出能力。将有源FBG-FP技术用于高倍增敏传感,实现了30倍增敏传感。4.从理论上研究了单路FBG-FP增敏传感系统和时分复用FBG-FP增敏传感系统的串扰问题。分别对串扰来源、大小、频谱进行研究,得出抑制串扰的系统设计方法。通过仿真计算、两基元系统和三基元系统对串扰理论进行验证,实现了串扰小于-40d B的时分复用FBG-FP增敏应变传感。5.研制了FBG-FP增敏传感的光纤加速度计和光纤矢量水听器。增敏后的光纤加速度计灵敏度提高了18超过25d B,分辨率水平改善超过15d B。增敏后的光纤矢量水听器灵敏度提高了4倍且具有优良的指向性。
[Abstract]:Fiber Bragg grating Fabry-Perot (FBG-FP) sensing system plays an increasingly important role in the field of fiber optic sensing because of its simple structure and high reliability. Optical fiber accelerometers, optical fiber vector hydrophones and other optical fiber sensors can not realize high sensitivity sensors with small size from mechanical structure due to the constraints of size and mechanical resonance. In this paper, the fiber Bragg grating Fabry-Perot cavity sensing system based on matching interference is used to improve the optical path of the FBG-FP sensing system by means of multiple reflected light pulses. The performance of the FBG-FP sensing system is greatly improved. The main innovations and achievements are as follows: 1. The optimal design scheme of each parameter of FBG-FP optical sensitizing sensing system is analyzed. The sensing performance of 1-order 9 order matching interferometry is studied theoretically and experimentally. It is verified that the system has the ability to improve the sensitivity and resolution level of FBG-FP sensor system. A new technique of two-order acousto-optic chopping, amplifying and filtering is proposed, which solves the problems of optical power fading and imbalance in high multiplier sensing, and successfully breaks through the sensitizing limit of conventional FBG-FP optical sensitizing sensing system. The background noise with 20 doubling sensitivity is reduced by about 11d B.3. A new active FBG-FP sensitizing sensing technique is proposed, which can not only solve the problem of optical power fading and imbalance in high multiplier sensitivity, but also have higher system integration and lower cost. The noise performance of active FBG-FP and the output capacity of high order pulse equalization are analyzed theoretically. The active FBG-FP technology is applied to the high multiplier sensing, and the 30 multiplier sensing. 4. 4. The crosstalk problem of single-channel FBG-FP sensitized sensing system and time-division multiplexed FBG-FP sensitized sensing system is studied theoretically. The source, size and spectrum of crosstalk are studied respectively, and the system design method of suppressing crosstalk is obtained. The theory of crosstalk is verified by two-element system and three-element system, and the time-division multiplexing (TDM) strain sensing of FBG-FP with crosstalk less than -40dB is realized. Fiber accelerometer and fiber vector hydrophone for FBG-FP sensitizing sensor are developed. The sensitivity of the fiber accelerometer is increased by 18 dB and the resolution level is improved by 15 dB. The sensitivity of the sensitized fiber vector hydrophone is increased by 4 times and has good directivity.
【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TP212;TN253

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