基于相位调制的干涉型光纤传感器研究

发布时间：2018-01-01 22:08

本文关键词：基于相位调制的干涉型光纤传感器研究　出处：《西北大学》2016年博士论文　论文类型：学位论文

【摘要】：光纤传感器以其结构灵巧、多参量测量、高灵敏度和易于组网等优点得到了广泛应用。本文研究了多种基于相位调制的干涉型光纤传感器,实现了对环境温度、湿度、折射率等参量的传感；并针对如何抑制和消除光纤传感器普遍存在的温度交叉敏感问题进行了研究和探讨,分别采用温度补偿技术来抵消温度波动对测量结果的影响,采用双参量同时测量技术来区分温度和待测物理量对测量结果的影响。具体内容如下：(1)理论上阐述了光纤中的模式概念和模式耦合方程；多模干涉和四种典型干涉仪的干涉理论及基于这些干涉结构的光纤传感器的工作原理；基于光纤Michelson干涉仪的光学相干层析成像技术(OCT)的理论基础和工作原理。(2)研究了基于多模干涉结构的光纤传感器。研制了一种基于单模光纤—多模光纤纤芯—单模光纤(SMCS)结构的折射率(RI)传感器,灵敏度为170nm/RIU;在SMCS折射率传感器的基础上,首次提出了一种利用这种折射率敏感结构的温度串扰特性来增强温度灵敏度的方法,研制了一种高灵敏度温度传感器。传感器由在SMCS外包裹一层具有较大热光系数的液体构成。由于热光效应,外界温度的变化会引起液体折射率发生改变,导致对折射率非常敏感的SMCS结构的特征波长发生漂移,再加上其本身对温度的响应,就可以得到一个叠加增强的温度灵敏度。实验结果表明,当包裹液体为去离子水时,温度灵敏度达到了358pm/℃,比固有灵敏度提高了30倍。这种利用折射率敏感结构的温度串扰特性来增强其作为温度传感器时的灵敏度的方法,为温度交叉敏感问题的研究提供了一种新的思路。(3)研究了基于Michelson干涉仪的光纤传感与成像技术。研制了一种基于Michelson干涉仪和高双折射(Hi-Bi)光纤的温度／折射率同时测量传感器,由3dB耦合器一臂末端熔接一小段Hi-Bi光纤探针构成。传感器对折射率和温度波动的响应是互相独立的,折射率和温度灵敏度分别为-30.1141 dB/RIU和-1.057 nm/℃,温度灵敏度达到了纳米量级；研制了一种基于Michelson干涉仪和光子晶体光纤(PCF)的温度/折射率同时测量传感器,由3dB耦合器一臂末端错位熔接一小段PCF探针构成,折射率和温度灵敏度分别为-102048.3 a.u/RIU和13 pm/℃。该传感器可以通过两个干涉臂分别传感温度和折射率信息,也可以进行双参量同时测量,具有很好的使用灵活性；搭建了一套采用光纤光路的谱域OCT系统,其在空气中的理论纵向分辨率和最大成像深度分别为16.8μm和21.5mm,实现了对彩绘颜料、壁画和翡翠样品的成像检测。(4)研究了基于Fabry-Perot干涉仪和聚乙烯醇(PVA)湿敏材料的光纤相对湿度(RH)传感器。研制了一种由一小段PCF熔接至SMF尾端并镀PVA薄膜构成的光纤RH探针,总长度约110μm,可以实现对环境温度和相对湿度的同时测量；研制了一种由一小段腐蚀了部分包层的细芯光纤(TCF)熔接至SMF尾端并镀PVA涂层构成的光纤RH探针,总长度约105μm,通过能量解调的方式实现对环境相对湿度的测量,可以避免温度串扰。这两种RH传感器的总长度都只有百微米左右,可以灵活地应用于狭窄空间中。(5)研究了基于线型Mach-Zehnder干涉仪(MZI)的光纤传感器。研制了一种基于单模光纤—色散补偿光纤—单模光纤(SDS)结构级联对折射率不敏感的光纤布拉格光栅(FBG)的温度/折射率同时测量传感器。SDS特征波长的折射率和温度灵敏度分别为232.8nm/RIU和11 pm/℃,FBG的温度灵敏度为8pm/℃,通过FBG实现温度校准；研制了一种在两段极短的多模光纤(MMF)之间夹熔一段色散补偿光纤构成的温度/折射率传感器,由两段MMF来激发和再耦合包层模式。传感器的温度和折射率灵敏度分别为118 pm/℃和66.32 nm/RIU;研制了一种基于MZI的温度和拉力或者温度和弯曲双参量同时测量传感器,由错位熔接至输入SMF端面的FBG后再熔接一小段极短的MMF和输出SMF构成。由于FBG的中心波长和干涉谱的特征波长对温度和拉力或温度和弯曲的响应灵敏度不同,只需根据关系矩阵即可求出环境的温度和拉力或者温度和弯曲信息；研制了一种由夹熔于两段SMF之间的空芯光纤(HCF)内壁镀一层氧化锌(ZnO)薄膜构成的温度传感器,通过镀膜很好地改善了输出光谱,传感器的温度灵敏度为25.24pm/℃。
[Abstract]:Optical fiber sensor with its flexible structure, multi parameter measurement, high sensitivity and easy networking and other advantages has been widely used. This paper studied a variety of interferometric fiber optic sensor based on phase modulation, the humidity of the environment temperature, refractive index sensing parameters; and on how to restrain and eliminate common optical fiber temperature sensor the cross sensitivity problem is studied and discussed, respectively, using the temperature compensation technology to offset the impact of temperature fluctuation on the measurement results, the two parameters simultaneous measurement technology to distinguish the effects of temperature and physical quantity to be measured on the measuring results. The specific contents are as follows: (1) the theory explains the concept and mode coupling equation for optical fiber the multimode interference; and four kinds of typical interferometer interference theory and working principle of optical fiber sensor based on the structure of the interferometer; fiber interferometer based on Michelson The technology of optical coherence tomography (OCT) theory and the principle of work. (2) studied the multimode interference optical fiber sensor based on the structure. The research and development of a single mode optical fiber and multimode fiber and single-mode fiber (SMCS) based on the structure of the refractive index (RI) sensor, the sensitivity of 170nm/RIU based on SMCS; the refractive index sensor, first proposed a temperature crosstalk using the refractive index sensitive structure method to enhance the temperature sensitivity, developed a high sensitivity of the temperature sensor. Sensor is wrapped in SMCS outer layer with large thermo optic coefficient of liquid. Due to the thermo optical effect, the temperature changes will cause the liquid refractive index changes, resulting in a characteristic wavelength of SMCS structure is sensitive to the refractive index of the drift, plus its responses to temperature, you can get a strong spirit of increasing temperature superposition Sensitivity. The experimental results show that when the package liquid of deionized water, the temperature sensitivity reaches 358pm/ DEG C, than the inherent sensitivity increased by 30 times. The temperature characteristics of crosstalk sensitive to the refractive index structure to enhance the sensitivity of the method as a temperature sensor, provides a new way to study the cross sensitivity problem the temperature. (3) of the optical fiber sensing and imaging technology based on Michelson interferometer is developed. A Michelson interferometer based on high birefringence (Hi-Bi) temperature / refraction rate of the optical fiber sensor at the same time, by the 3dB coupler arm end welding a short Hi-Bi fiber probe. The response of sensor the refractive index and temperature fluctuations are independent of each other, the refractive index and temperature sensitivity were -30.1141 dB/RIU and -1.057 nm/ DEG C, the temperature sensitivity reaches nano scale was developed based on Michelson; Interferometer and photonic crystal fiber (PCF) temperature / refractive index and measuring sensor composed of 3dB coupler arm welding end dislocation of a short PCF probe, refractive index and temperature sensitivity were -102048.3 a.u/RIU and 13 pm/ C. The sensor can through two interference arms are respectively the refractive index and the temperature sensing information, can also be double parameter measurement at the same time, has a good flexibility; build a OCT system using the spectral domain optical path, the theory of vertical resolution in the air and the maximum imaging depth of 16.8 m and 21.5mm, the realization of pigments, imaging murals and jadeite jade samples (4). Study on the Fabry-Perot interferometer and polyvinyl alcohol (PVA) based on the humidity sensitive material fiber relative humidity (RH) sensor is developed. A short PCF fused to SMF end and PVA film coating of optical fiber RH probe, total A length of about 110 m, can realize the measurement of environmental temperature and relative humidity at the same time; developed a kind of corrosion by a small piece of thin core fiber part cladding (TCF) fused to the optical fiber RH probe SMF end and plating PVA coating composition, a total length of about 105 m, achieved through the measurement of relative humidity the environmental energy demodulation method, can avoid the temperature change. The total length of the two RH sensors are only 100 microns, can be flexibly applied in narrow space. (5) of interferometer based on linear Mach-Zehnder (MZI) optical fiber sensor is developed. A single mode optical fiber and dispersion compensation fiber - based on single-mode fiber (SDS) is not sensitive to the structure of cascaded fiber Prague grating on the rate of refraction (FBG) temperature / refractive index and temperature sensitivity and measuring sensor.SDS characteristic wavelengths were 232.8nm/RIU and 11 pm/ C FBG temperature sensitive The degree of 8pm/ C, through FBG to achieve temperature calibration; developed a multimode fiber in two short (MMF) between a dispersion compensating fiber consisting of fused temperature / refractive index sensor consists of two segments of MMF to stimulate and re coupling of cladding modes. The temperature and refractive index sensor sensitivity rate was 118 pm/ C and 66.32 nm/RIU respectively; at the same time, developed a measurement sensor MZI temperature and the temperature and bending tension or double parameters based on by offset splicing to the input end of the SMF FBG after welding a short short MMF and output SMF. Because the FBG central wavelength and the wavelength of the interference spectrum characteristics of temperature and the tension or bending and temperature sensitivity of different, only matrix can be obtained according to the relationship between environment temperature and temperature and tension or bending; developed a clip by melt in between two sections of SMF hollow fiber (HCF) with a layer of inner wall coating The temperature sensor made up of the Zinc Oxide (ZnO) film improves the output spectrum well through the coating, and the temperature sensitivity of the sensor is 25.24pm/ C.

【学位授予单位】：西北大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP212

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