【作者】 郭玉静；

【导师】 张颖；

【作者基本信息】 燕山大学 ， 测试计量技术及仪器， 2006， 硕士

【摘要】 溶液浓度是表征溶液特性的主要参量之一。对溶液浓度的测量与控制在造纸、化工、制糖、食品、制药等行业中有着广泛的应用。长周期光纤光栅传感器以其良好的电气绝缘性、抗电磁干扰性、抗腐蚀性、体积小、重量轻、灵敏度高、复用性强等特点,弥补了传统溶液浓度测量手段测量缺点,是具有良好应用前景的溶液测量传感器。本文以长周期光纤光栅(Long Period Grating)为研究对象,对LPG的理论和传感技术进行深入的研究。提出了LPG测量溶液浓度的方案,对LPG溶液浓度技术进行了深入的理论和仿真研究,并进行了实验验证。文中概括地介绍了光纤光栅制作及其应用技术的研究状况。推导出LPG导模与包层模的耦合关系;对LPG导模和包层模有效折射率、耦合系数进行了计算;分析研究了LPG参数对光栅谱形的影响,得出合理设计光栅参数的理论依据。针对LPG对外界折射率敏感的特性,给出了LPG中心波长变化量与外界折射率的关系表达式,并用Matlab进行模拟计算,给出了LPG在不同参数下的传感特性。针对NaCl溶液浓度传感,设计了一套LPG传感实验装置,并分别用不同LPG进行了传感实验研究。对于不同的光栅,光栅中心波长与NaCl溶液浓度均成非线性关系,结合实验数据和LPG折射率传感公式得出光栅中心波长与浓度关系式,关系式与测量数据拟合度较高,其计算值与测量值之间误差小于0.007 nm;不同的光栅有不同的传感区域;光栅在溶液的低浓度端和高浓度端分别具有不同的灵敏度。因此,采用LPG进行溶液浓度传感时,应针对不同的溶液和不同的浓度范围选择不同的光栅。更多还原

【Abstract】 Concentration is an important parameter of solution. It is important to measurement and control towards solution concentration in the areas of paper making, chemical, refine sugar, food, medicine and so on. Fiber grating has the advantages of electric insulation, resistance of the interference of electromagnetism, anti-erosion, small volume, light weight, high sensitivity, strong repetition and so on. It can fetch up the disadvantages in traditional measurement. Thus it’s a promising sensor of solution concentration.This paper takes long period grating (LPG) as the object. We study the theory of LPG and sensing technique. We propose the measurement towards solution concentration using LPG. We study on the solution concentration sensing theory and simulation. Finally we take an experiment of LPG sensing. The paper generally introduces the study of making and implication of fiber gratings. We deduced the coupling between the guided mode and the cladding mode. We also introduce the calculation of guided mode、cladding mode refractive index and coupling coefficient. We study the effect of grating parameter on the spectrum. The formula of resonance peak shift is deduced. We have the sensing characters with different parameters of LPG under the simulation using Matlab.The paper designs a solution concentration sensing equipment using different LPGs, and different concentrations of a set of NaCl are measured experimentally. The relationships of LPGs’resonance wavelength and concentration are all non-linear. The function of resonance wavelength and NaCl concentration can be deduced from experiment data and formula of LPG refractive index sensing, and the max error is 0.007 nm; Different LPGs have different effective sensing areas; The sensitivities of LPGs are different when NaCl concentrations are at low concentration and high concentration. So when the solution concentration is measured using LPG, LPG should be selectedreasonably according to different solutions and different concentration spans. The sensing of solution concentration can be proceeded after calibration.更多还原