【作者】 赵志胜；

【导师】 高锦岳；

【作者基本信息】 吉林大学 ， 光学， 2007， 硕士

【摘要】 光纤光栅(fiber grating)是一种新型的光无源器件。作为光子研究领域的一种新兴技术,以光纤光栅为基本传感器件的传感技术的研究应用近年来受到普遍关注,目前,以布拉格光纤光栅(FBG: fiber Bragg grating)为传感器件的传感器已成为研发主流。本论文以光纤光栅、传感器、温度增敏调谐装置为研究对象,主要包括以下几方面的内容:第一部分概述了传感器的发展、光纤光栅的发展、光纤光栅传感器的特点及国内外基于光纤光栅传感器的发展现状。第二部分从制作光纤光栅的物理机制出发,对各种写入方法进行比较,分析了光纤光栅的分类及不同应用。第三部分应用耦合模理论推导了实验用布拉格光纤光栅的特性,分析了光纤光栅传感器实验用和常用解调技术的原理及优缺点。第四部分提出了一种灵敏系数可调谐的光纤光栅温度调谐实验装置,详细推导了其调谐原理,阐明了设计方法,实验得到了较高的温度调谐效率,实验结果和理论符合很好。这种装置最大的特点在于通过对其长度的设计,可以使其温度灵敏系数可调,也为我们实验所证实,这为我们进一步优化设计温度调谐装置以使其应用于高精度测量领域提供了重要的依据和参考价值。更多还原

【Abstract】 With the development of society, people have an increasing demand for information. As one of the three mainstays of modern information technology, the information collection technology (sensor technology) is becoming more and more important.Fiber Grating is a new type of passive optical components.It can change or control the behavior of optical transmission in the region. As a new technology of photon research, Fiber Bragg Grating(FBG) sensors are attracting considerable interests in research and applications.In this paper, we research on fiber grating, sensors, a scheme of temperature sensitivity enhancement . Including the following aspects :1. Generally introduce the domestic and foreign development and application of sensors, FBG and the advantages of FBG sensors compared to the other sensors such as anti-interference capability, self-reference, absolute parameter of wavelength. 2. Analyze the physical mechanism that fiber grating is made of in use of photosensitive fiber material, and compare the two categories of effective methods: interference fabrication and point-by -point fabrication; it can be divided into uniform and non-uniform fiber grating.3. Analyze the optical transmission with the coupled-mode theory and analytical expression of fiber grating characteristic. The demodulation technology of signals is very important in Sensor System, the coding of which is wavelength. We analyze the application and principle of the currently used demodulation.4. We analyze the principle of FBG tuning , several schemes.Research on temperature sensor and sensitivity enhancement of FBG.The sensing FBG with low temperature sensitivity ,only 0.0lnm/℃,is commonly encapsulated by a drive material with high thermal expansion coefficient,which is hardly developed due to the restriction of driven material.A new scheme is proposed as shown in figure 1. The two surface material M 2 with low thermal expansion coefficient are glued to the ends of bottom material M 1 with high one.Then FBG is glued on the endpoints of M 2. This tuning device is designed to provide a equivalent drive material with a thermal expansion coefficient that can be changed not only by the materials , M 1and M 2,but also by changing the size of the device.So theoretically this tuning device can be designed with any high resolution according to practical requirements and break through the restriction of thermal expansion coefficient of drive material fundamentally.The fitting line of results is shown in figure 2. The experiment result indicates that within 4.6°C,the bragg wavelength moves 3.14nm .The temperature sensitivity is 0.70316 nm/°C,which is 70 times higher than that of the bare FBG and matches the theoretical result 0.7073nm/°C very well.Due to the 0.05 nm resolution of our optical spectrum analyzer , the resolution temperature measurement is <0.07°C. The linearity of the temperature response curves is0.9997.Because FBG is extended axially, there are not chirped effects of the reflection spectrum as polymer packaged that is hard for demodulation. The reflection spectrum remains same during the whole test.The FBG we use is written without coating. Its mechanical strength is low so that the tuning range is relatively small, which special written FBG with high mechanical strength would greatly increase. In addition, both shorter grating and more suitable material with high coefficient of thermal expansion are advantaged for temperature sensitivity coefficient and size of the device.The greatest advantage of this device is its adjustable temperature coefficient of sensitivity by designing the length. In the experiment, in order to change the length flexibly, we used clamp to replace glue to fix devices and achieved a change in the tuning efficiency, which accords with the theory. This study provides an important basis and reference values, and this device can be further improved by materials and production processes. In the field of high-precision measurement it is expected a great value.更多还原