新型光纤光栅温度自补偿方法理论分析

为了解决光纤光栅作为应变传感器使用时的温度应变交叉敏感问题,提出了一种全新的光纤光栅温度补偿方法,该方法最大特点是利用一个光纤光栅同时实现了温度自动补偿与应变测量。该方法基于材料的热应力原理,简称为基于材料热应力的光纤光栅温度补偿方法。通过理论分析表明:温度灵敏度系数与应变灵敏度必须精确测定,否则会影响结构设计;应变元件与温度补偿元件的面积之比对温度补偿效果很大,原则上应小于0.5,因此结构半径的加工误差对温度补偿影响很大。应变元件与温度补偿元件的长度比对温度补偿效果基本可忽略,因此,原则上在不影响温度补偿效果的前提下,尽量提高温度补偿元件与应变元件的长度比。     

带宽调制型单光纤光栅温变无补偿位移传感

报道了利用反射谱带宽调制和光强差分探测技术实现单一光纤光栅温变无补偿位移精确测量的新方法。设计了一种结构新颖的曲臂梁位移传感装置,结合光波导理论与材料力学原理分析了光纤光栅在高斯应变作用下光栅反射谱侧向梯度展宽的成因,理论推导了特殊结构梁在外力作用下光栅反射谱带宽/反射光强与压力之间的响应关系。光栅反射谱侧向梯度展宽的同时反射光强线性增加,利用光强差分检测方法消除光源出光抖动的影响,提高了位移测量精度。基于带宽调制的光纤光栅位移传感方法免受温度变化的影响,在-10℃~80℃的温度变化范围内,测量误差小于1.2%,实现了单光纤光栅温变无补偿位移测量。     

光纤Bragg光栅应力传感中温度交叉敏感问题研究

针对光纤Bragg光栅应力传感中温度交叉敏感的问题,设计了一种有效的无源温度补偿方法和补偿结构。通过理论模拟,分析了M值不同时补偿效果曲线的变化,从中得到了补偿效果最好时的M值;得出了不同预应变情况下的温度特性曲线,从中找出了温度特性被完全补偿时的预应变的值;分析了温度补偿中出现过补偿和欠补偿现象的原因。通过该方法,有效地解决了光纤Bragg光栅传感中的温度交叉敏感问题。温度补偿后可以满足对光纤光栅温度稳定性要求较高的光纤传感、通信等领域的需要。     

动态匹配光栅解调传感系统温度补偿研究

采用一对辅助匹配光纤光栅,结合基于MAX1968EUI芯片闭环自动控制,设计了一种半导体小型温度控制系统.通过控制传感光栅反射峰值变化,使匹配光栅温度变化与传感光栅周围环境温度变化相匹配,实现了动态匹配光栅解调方案的应变测量系统温度补偿,消除了光纤光栅传感器温度、应变交叉敏感效应对传感系统测量应变的影响.解调系统同时采用一支微测力传感器作为解调系统的输出,消除了传统动态匹配光栅解调系统中压电陶瓷磁滞效应对测量结果的影响.实验结果表明,温度变化对系统应变测量影响误差小于2％,传感系统的线性优于0.999 5.     

光纤布拉格光栅法布里-珀罗腔纵模特性研究

分析了光纤布拉格光栅构成的法布里-珀罗（F-P）腔的透射谱特性，讨论了光栅带宽，反射系数相位因子以及腔长对F-P腔透射特性的影响，并对F-P腔随温度和应变的特性进行了分析，然后给出如何设计在光栅中心耦合波长处单模运转的法布里-珀罗腔.并提供了数值模拟结果和实验结果. 关键词： 光纤布拉格光栅 法布里-珀罗（F-P）腔 光纤激光器     

Strain and temperature discrimination technique by use of A FBG written in erbium doped fiber

We propose and demonstrate strain and temperature discrimination technique using a single fiber Bragg grating (FBG) written in the core of an erbium doped fiber. We observed that amplified spontaneous emission power varying linearly from the erbium doped fiber with temperature which determines temperature changes and strain is estimated by subtracting the wavelength shift due to temperature change, from the measured shift corresponding to the dip in the transmission spectrum of the FBG. A simple and compact FBG sensor is presented with improved rms errors of 21.2 μ? and 1 °C over ranges of 0–800 μ? and 40–95 °C, respectively. The sensor is shown to have strain and temperature sensitivity of 0.8 pm/μ? and 12 pm/°C.     

基于封装光纤Bragg光栅传感器的混凝土应变监测试验研究

研究了光纤Bragg光栅封装工艺,提出并实现了两种封装光纤Bragg光栅传感器:工字型钢管封装光纤Bragg光栅应变传感器及钢管封装光纤Bragg温度传感器。研究了传感器的埋设工艺,采用金属丝固定法、钢管抽出法两种方法进行了埋设。将它们埋入到钢筋混凝土梁中,实现对混凝土的拉、压应变及温度的测量。结果显示,在试验梁弹性阶段,可以较为准确的监测混凝土应变。     

A novel fiber Bragg grating high-temperature sensor

A novel fiber Bragg grating (FBG) sensor for the measurement of high temperature is proposed and experimentally demonstrated. The interrogation system of the sensor system is simple, low cost but effective. The sensor head is comprised of one FBG and two metal rods. The lengths of the rods are different from each other. The coefficients of thermal expansion of the rods are also different from each other. The FBG will be strained by the sensor head when the temperature to be measured changes. The temperature is measured basis of the wavelength shifts of the FBG induced by strain. A dynamic range of 0–800 °C and a resolution of 1 °C have been obtained by the sensor system. The experiment results agree with theoretical analyses.     

小直径光纤光栅的研制及传感交叉敏感研究

研究了小直径光纤光栅的研制以及传感中的温度应变交叉敏感问题.首先根据耦合模理论,分析了小直径光纤Bragg光栅光谱特性,确定了包覆层为80 μm的单模光纤加工成中心波长为1 528 nm的Bragg光栅的栅长及周期,并研究了小直径光纤光栅与解设备之间的连接方式.其次利用等强度梁的变形特点,结合矩阵法,提出基于等强度悬臂梁双Bragg光纤光栅矩阵算法,对小直径光纤Bragg光栅的交叉敏感问题进行研究.温度和应变的实验辨别误差分别为5%和6%.实验结果表明,该方法可以分离温度和应变对光纤Bragg光栅传感的影响.采用该方法去除交叉影响,K矩阵始终存在逆矩阵,因此对所采用的光栅无特殊要求,从而扩大了光纤光栅选用范围,并将温度和应变识别出来.     

Analysis on strain transfer of a pasted FBG strain sensor

Optical fiber is not in direct contact with the material host in practice, so the strain measured by the Fiber-optic Bragg Grating (FBG) sensor is not the true strain. The transfer mechanism between the measured strain and the true strain depends on mechanical properties of fiber, protective layer, substrate, adhesive layer, and the material host. This paper analyzes the transfer mechanism of strain in detail, and proposes the shear stress distribution of polynomial form, and establishes the transfer function of strain. This paper also analyzes the influence on length of FBG sensor, adhesive layer thickness and elastic modulus on strain transfer coefficient in detail. The theoretical guidance for the practical application of the FBG sensor is given through the strain transfer analysis.     

用双周期光纤光栅实现温度和应变的同时测量

介绍了光纤光栅传感器的一般原理，分析了长周期光纤光栅和Bragg光纤光栅的应变和温度响应机理。结果表明，长周期光纤光栅和Bragg光纤光栅的温度和应变灵敏度不仅与纤芯参数和光栅周期有关，还依赖于包层参数。在同一根光纤上先后写入长周期光纤光栅、Bragg光纤光栅，利用长周期光纤光栅和Bragg光纤光栅基模与包层模耦合时温度和应变灵敏度的不同，实现应变和温度的同时测量。     

基于非线性啁啾光纤光栅实现的色散可调谐

从原理上证明了一种基于非线性啁啾光纤光栅以及光纤光栅的温度特性的色散可调谐方案.实验证明在25.5℃的温度变化范围内,光纤光栅对1550.43nm波长的色散补偿量从759.1ps/nm上升到1659.9ps/nm,色散调谐范围达到900ps/nm,这个方案具有对补偿波长和特定补偿波长所需要的色散补偿量同时进行调谐的特点.     

Design of fiber Bragg grating-based Fabry–Perot sensor for simultaneous measurement of humidity and temperature

A new sensor for simultaneous measurement of humidity and temperature is proposed. The sensor consists of Fabry–Perot cavity formed by two identical uniform fiber Bragg gratings. To make the cavity serves as humidity sensor, moisture sensitive polymer, which is polyimide, is coated on the FBG and on the cavity with different thickness. When the sensor is exposed to the relative humidity change, the polyimide will expand and stretch the fiber and induces strain on the FBG and on the cavity. The induced strain alters the grating period, cavity length and effective refractive index of fiber. The simulation results show that the humidity sensitivity and thermal sensitivity are 1.92 pm/%RH and 8.87 pm/°C, respectively, for polyimide coating thickness of 10 μm on the FBG and 15 μm on the cavity.     

分体插接式光纤光栅应变片设计与实现

提出一种适合作为二次变换元件使用的通用型应变传感预制结构——光纤光栅应变片.它以裸Bragg光栅为研究对象,采用分体式设计方法把敏感光栅与连接光纤分别封装于独立的基体中,并通过两个基体相互之间的插入实现了Bragg光栅与测量光路的机械连接.理论分析和实验研究表明:光纤光栅应变片具有与Bragg光栅相同的反射谱,其测量线性度好,灵敏度高,温度误差则随被测试件性质不同而变化,当试件材料与基底材料一致时,温度误差可以忽略.     

高速光通信系统中光纤光栅色散补偿研究

通过对光栅制作过程的优化设计，解决了光纤光栅温度稳定性、纹波系数、带宽、偏振模色 散补偿等关键技术，所制作光纤光栅已经达到温度系数小于00005 nm/℃，带宽大于14 nm，纹波系数小于50 ps，色散量超过 -1000 ps/nm的先进水平. 采用琼斯矩阵本征值法较 精确地测量了光栅的偏振模色散，并对其进行了补偿，光纤光栅色散补偿器的偏振模色散由 补偿前的91406 ps改善为补偿后的01521 ps. 在此基础上，成功地建立了一个稳定可靠 、速率为40 Gb/s，传输链路为122 km G 关键词： 高速光通信系统 普通单模光纤 光纤光栅 色散补偿     

On a fiber grating sensor system with the capacity of cross-sensitivity discrimination

A novel fiber Bragg grating (FBG) sensor system based on an interrogating technique by two parallel matched gratings was designed and theoretically discussed. With an interrogation grating playing the role of temperature compensation grating simultaneously, the wavelength drifts induced by temperature and strain were discriminated. Additionally, the expressions of temperature and strain were deduced for our solution, and dual-value problem and cross sensitivity were solved synchronously through data processing. The influence of the FBG's parameters on the dynamic range and precision was discussed. Besides, the change of environment temperature cannot influence the dynamic range of the sensor system through temperature tuning. The system proposed in this paper will be of great significance to accelerate the real engineering applications of FBG sensing techniques.     

Simultaneous strain and temperature measurement with a single fiber Bragg grating based on the polarization properties analysis

In this paper, a new technique for discrimination of temperature and strain exploiting the polarization properties of a single normal fiber Bragg grating (FBG) is firstly proposed and experimentally demonstrated. The spectral characterization of the differential group delay (DGD) of the FBG is studied. The evolution of the DGD response of the FBG as a function of temperature and strain is analyzed. The numerical simulations and experimental results suggest that implementing two independent measurements of the resonance wavelength shift and the changes of the DGD can discriminate the temperature and strain effects.     

可分离温度影响的FBG应变测量方法

光纤布拉格光栅在通信和传感领域具有广泛的应用。利用光纤布拉格光栅中心波长的偏移，可以测量温度和应变等多种物理量，但必须解决光栅对温度和应变的交叉敏感问题。该文简要分析了光纤光栅作为传感器的基本原理及其优点，设计了利用参考光栅法分离温度影响以及利用掺铒光纤的自发发射放大特性分离温度影响的2种应变测量方法。最后，介绍了一种利用倾斜光纤光栅的主模和边模对布拉格光栅中心波长的偏移进行解调的方法，该方法成功地分离了温度对应变测量的影响。     

用布喇格光纤光栅传感器测定口腔复合树脂材料光固化收缩与温度演化特性

复合树脂材料已成为重要的牙齿美容修复材料.本文利用两种布喇格光纤光栅传感器测定了口腔复合树脂材料在光固化过程中的收缩与温度演化特性.一种为普通的光纤布喇格光栅,另一种为经过了化学镀镍的光纤布喇格光栅,同时埋入复合树脂样品中,用光照射使其固化,测得光纤布喇格光栅在固化过程中温度和应力随时间的演化曲线.实验结果表明,在光固化过程中,因为聚合反应,树脂产生了强烈的收缩应力和温度变化.掌握复合树脂的光固化收缩特性和温度变化特性对不断改良材料性能以及优化口腔材料的治疗效果具有实际意义.     

用布喇格光纤光栅传感器测定口腔复合树脂材料光固化收缩与温度演化特性

复合树脂材料已成为重要的牙齿美容修复材料.本文利用两种布喇格光纤光栅传感器测定了口腔复合树脂材料在光固化过程中的收缩与温度演化特性.一种为普通的光纤布喇格光栅,另一种为经过了化学镀镍的光纤布喇格光栅,同时埋入复合树脂样品中,用光照射使其固化,测得光纤布喇格光栅在固化过程中温度和应力随时间的演化曲线.实验结果表明,在光固化过程中,因为聚合反应,树脂产生了强烈的收缩应力和温度变化.掌握复合树脂的光固化收缩特性和温度变化特性对不断改良材料性能以及优化口腔材料的治疗效果具有实际意义.