【作者】 刘慧；

【导师】 杨杭洲；

【作者基本信息】 西北大学 ， 光学， 2017， 硕士

【摘要】 双参量光纤传感器可同时实现两个物理参量的测量,其结构小、耐高温、有韧性、抗电磁干扰等优点在工程监测应用方面深受关注。温度是一个影响其他物理量的宏观参量。在传感器设计中,被测物理量与温度信息的区分测量一直是该领域的研究重点。在一些特殊应用领域,温度变化幅度较大会导致检测结果严重偏离。基于光纤光栅和干涉型光纤结构的光纤传感器是一种能较好的区分温度信息和其他被测参量的双参量检测技术。本文研究的内容是通过光纤干涉结构结合光纤布拉格光栅的方式,制作出双参量光纤传感器,并对其传感性能进行了理论分析和实验研究。一种是通过光纤干涉结构级联热重生光栅的方法,得到可以在600℃高温环境中操作的温度和应变传感器。另一种是利用在光子晶体光纤纤芯上刻蚀布拉格光栅的方式,实现一个灵敏度较高的温度-曲率测量传感器。具体内容如下:利用内径为19μm、30μm和75μm的空芯光纤制作出三种法布里-珀罗干涉结构。分析相应的光谱得出空芯内径越大的结构越容易激发高阶模式,由此使其温度、应变响应越敏感。实验中,它们的温度灵敏度从0.82～0.99pm/℃,而应变灵敏度从1.23～2.36pm/με,这应证了以上的理论分析。为制作出一个稳定性较高的高温应变双参量传感器,通过光纤布拉格光栅后级联一段由19μm空芯光纤制作成的光纤干涉结构来实现,该传感器的温度和应变测量范围分别为19～600℃和0～600με,且其特性矩阵的条件数为12.09。通过在厚壁柚子型六孔光子晶体光纤的两端熔接多模光纤,设计并制作出基于马赫-曾德干涉原理的光纤干涉结构。由于多模光纤和光子晶体光纤之间存在纤芯失配,激发出高阶模式,提高了马赫-曾德干涉结构的温度与弯曲灵敏度。为了实现温度与弯曲的同时测量,在干涉结构中光子晶体光纤纤芯上刻写了光纤布拉格光栅,制作出温度弯曲双参量光纤传感器。实验结果表明:该传感器在10～22.4m-1的范围内,干涉波长得到的弯曲灵敏度为-1.03nm/m-1,是布拉格光栅波长弯曲灵敏度的343倍;在8～100℃的测量范围内温度灵敏度为60.3pm/℃。更多还原

【Abstract】 Fiber optic sensors benefit from their own advantages,widely used in environmental monitoring and industrial production.A fiber sensing structure can sense a single parameter to achieve temperature,strain,bending,refractive index and level measurement so on.However,the fiber sensor itself is inherently sensitive to the temperature.When the temperature changes in a larger range,the single parameter sensor structure on the temperature sensitivity problem will be highlighted.Based on the fiber grating and interference type fiber structure of the dual-parameter fiber sensor can better distinguish between temperature and other parameters of the change.In this paper,two kinds of dual-parameter optical fiber sensors are fabricated by cascade and etching Bragg grating on the fiber interference structure,and the sensing performance is analyzed theoretically and experimentally.The dual-parameter fiber optic sensor is formed by cascading and etching a fiber Bragg grating of a fiber interference structure,and in the optical fiber interference structure is formed by arc discharge welding.As a result,temperature and strain sensors that can operate at high temperatures of 600℃,which is obtained by cascading the regenerated gratings.The method of etching the Bragg grating on the photonic crystal fiber core is proposed to realize a high sensitivity temperature and curvature measurement sensor.The details are as follows:Using the inner diameter of 19μm,30μm and 75μm hollow fiber to produce three Fabry-Perot interference fiber structures.Analysis of the corresponding spectrum to get the larger hollow diameter of fiber more easily excited high-order mode,and then its temperature and strain response will be more sensitive.In the experiment,the corresponding temperature sensitivity increased from 0.82pm/℃ to 0.99pm/℃,while the strain sensitivity increased from 1.23pm/με to 2.36pm/με,which should be the above theoretical analysis.In order to fabricate a stable high temperature and strain dual-parametric sensor,a fiber interference structure made of 19μm hollow fiber is cascaded after fiber Bragg grating.The sensor temperature and strain measurement range were 19～600℃ and 0～600με,and its characteristic matrix conditions for the 12.09.The optical fiber interference structure based on the Mach-Zehnder interference principle is designed and fabricated by welding multimode fiber at both ends of six-hole thick grapefruit-type photonic crystal fiber.Due to the existence of core mismatch between multimode fiber and photonic crystal fiber,this will excited a lot of high-order mode,so as to improve the temperature and bending response sensitivity.In order to realize the simultaneous measurement of temperature and bending,a fiber Bragg grating is written on the core of the photonic crystal fiber in the fiber interference structure to fabricate a temperature-bending dual-parametric sensor.The experimental results show that the sensitivity of the sensor is-1.03nm/m-1 in the range of 10～22.4m-1,which is 343 times of the bending sensitivity of the Bragg grating.In 8℃ to 100℃ the temperature sensitivity is 60.3 pm/℃.更多还原