【作者】 张颖；

【导师】 王新顺；

【作者基本信息】 哈尔滨工业大学 ， 物理学， 2019， 硕士

【摘要】 近年来,光纤传感系统受到越来越多的关注,与传统的电学传感系统相比,光纤传感系统抗电磁干扰能力强,体积小,重量轻,机械性能好,并对温度、湿度、压强等外界条件的变化更加灵敏。本文主要研究了光纤法布里珀罗温度和压强传感器、光纤光栅湿度传感器的传感特性,实验结果显示光纤传感器有更好的灵敏度和精度,在响应时间上也优于电学传感器。本文主要研究内容如下:研究了光纤温湿度传感器的制备和封装方法,并实验测量了传感器的特性。温度探头的制备利用飞秒激光加工技术,在光纤端面刻蚀一个50μm×70μm的微腔。然后通过电弧放电熔接法形成光滑内壁的法布里珀罗腔,再将高热光系数的环氧树脂注入法布里珀罗腔内制备温度传感结构。湿度传感探头采用浸涂法在光纤布拉格光栅(FBG)区涂覆一层聚乙烯醇(PVA)薄膜,通过PVA吸水膨胀导致FBG周期变化来进行湿度传感。制备的传感探头均采用石英管,金属外管和PE铠装保护套封装。实验测量温度传感器的灵敏度为390pm/℃,湿度传感器的灵敏度为3.4pm/%RH。将封装好的光纤温湿度传感器应用于在烟气的温湿度测量,测量结果与传统电学传感器相比具有更高的灵敏度和更快的响应时间。制备出了基于光学游标效应的光纤空泡压强传感器,并实验测量了传感器的传感特性。利用电弧放电技术先将单模光纤与空心光纤(SCT)熔接在一起,然后将电极放在距离熔接点180μm处放电熔断,使其末端形成一个小气泡,不断调整电极的位置使其逐渐靠近末端使气泡越来越大形成一个法布里珀罗空气腔;然后采用飞秒激光在距离空气腔左壁81μm处的单模光纤内直写形成一个反射面,实现双法布里珀罗腔级联的光学游标效应。理论分析了两个法布里玻罗腔不同的腔长比对游标包络周期的影响,实验测量基于游标效应的空泡压强传感器压强灵敏度为3.97nm/Mpa,温度灵敏度为109pm/℃,可以实现温度和压强双参数传感测量。设计并装配了便携式光纤传感解调一体机。将制备的温湿度传感器与压强传感器与工业微电脑以及光纤光栅解调仪集成,设计并装配了一套完整的光纤传感解调一体机,使整套解调设备更加小型化。该设备可以实现多种测试环境下参数的原位监测。在硬件方面,主要采用3D绘图软件Solidworks分别对微电脑以及解调仪的固定外壳进行设计,然后使用3D打印机制作样机零件并装配;在软件方面,利用Labview进行光纤光栅解调仪初始化及测量参数计算,优化后的软件可以实现八通道同时进行测试,并实时显示当前环境的参数。更多还原

【Abstract】 In recent years,optical fiber sensing systems have received more and more attention.Compared with traditional electrical sensing systems,optical fiber sensing systems have strong electromagnetic interference resistance,small size,light weight,good mechanical properties.Changes in external conditions such as temperature,pressure,refractive index and vibration are more sensitive.In this thesis,the Fabry-Perot temperature sensor,pressure sensor and the fiber grating humidity sensor are used to replace the original electrical sensor.The experimental results show that the optical sensor has better sensitivity,accuracy and faster response time than electrical sensors.The main contents of this thesis mainly include the following parts:The preparation and packaging methods of the fiber optic temperature and humidity sensor were demonstrated,and the characteristics of the sensor were measured experimentally.Based on femtosecond laser processing technique,a 50μm×70μm microcavity was etched on the fiber end face,and Fabry-Perot cavity is formed by arc discharge technology for temperature sensing,and then a high thermal coefficient epoxy resin is injected to the Fabry-Perot cavity by using a needle tube.The outermost part adopts metal tube to package,and the tail fiber adopts armored optical fiber to package.The influence of the microcavity size and the loss in the manufacturing process on the reflectance spectrum was analyzed theoretically.The sensitivity of the probe measured by the experiment could reach 390pm/℃;the humidity sensing probe is coated with a polyvinyl alcohol(PVA)film in the Bragg fiber grating area through dip coating method.The outermost part adopts open-hole metal tube to package,and the tail fiber also adopts armored optical fiber to package.The packaged optic fiber temperature and humidity sensor is applied to the measurement of the flue gas,and the measurement result show that the optic fiber sensor has higher sensitivity and faster response time than the conventional electric sensor.The preparation of fiber-optic bubble sensor based on optical Vernier effect was fabricated,and the sensing characteristics of the sensor were measured experimentally.Using arc discharge technology,the single-mode optical fiber and silica capillary tube(SCT)are spliced together,and then the electrode is placed at a distance of 180μm from the fusion point,and a small bubble is formed at the end,adjusting the position of the electrode gradually to the end and make the bubbles bigger and bigger to form a Fabry-Perot air chamber,then a femtosecond laser is used to write a reflection surface directly in the single-mode optical fiber at a distance of 81 μm from the left wall of the air cavity to realize the optical Vernier effect.The influence of the different cavity length ratios of the two Fabry-Perot chambers on the envelope period is theoretically analyzed.The experimental pressure sensitivity of the sensor with the Vernier effect by the could reach 3.97nm/Mpa,the temperature sensitivity is 109pm/°C.A portable fiber optic sensor analysis machine was designed and assembled.The temperature sensor,the humidity sensor and the pressure sensor are integrated with industrial microcomputer and fiber Bragg grating demodulator.The device enables in-situ monitoring of parameters in a variety of test environments.In terms of hardware,the 3D drawing software Solidworks is mainly used to design the outer shell of the microcomputer and the demodulator,and then the assembly parts are assembled and assembled using the 3D printer.In terms of software,use Labview for initialization of FBG demodulator and calculation of measurement parameters.Eight channels can be used simultaneously and the corresponding parameters of the current environment can be displayed in real time.更多还原