【作者】 高少锐；

【导师】 何赛灵； 张阿平；

【作者基本信息】 浙江大学 ， 光学工程， 2014， 博士

【摘要】 光纤光栅是一种重要的无源光纤器件,在光纤通信、光纤传感及其它光纤技术领域中有着重要的应用,它的出现是光纤技术领域的一个里程碑。本论文针对新型光纤光栅传感技术和高温光纤光栅制作技术,开展了深入的理论和实验研究。本论文首先介绍了光纤的历史背景和光纤光栅的发展历程；然后介绍了光纤光栅在通信和传感中的应用,讨论了光纤光栅传感的分类和市场前景,并对光纤光栅传感的研究热点进行总结。接着探讨了光纤的光敏性；介绍了光纤光栅的理论分析工具(包括衍射理论,耦合模理论和传输矩阵法)；介绍了光纤光栅的分类,并给出了各种不同类型光纤光栅的光谱；简述了几种常见的光纤光栅制作技术以及本实验室的载氢装置和光纤光栅制作系统。本论文研究和发展了一种基于光热光纤布拉格光栅的新型流速／流量传感技术。光热光纤光栅是一种新型光栅器件,其特殊的光热转换机制和波长光调谐特性使得光热光纤光栅具备许多独特的应用。在分析光热光纤温度分布和热线测速技术的基础上,提出了基于光热光纤布拉格光栅的全光纤型气体流速传感器和微流控芯片流量传感器,结合光纤光栅解调技术,详细研究了不同条件下传感器的波长响应、灵敏度、响应时间,实现了高分辨率、高灵敏的流速／流量传感。本论文还提出了基于光热光纤长周期光栅的带主动温度补偿的折射率传感器。通过对光热光纤长周期光栅的温度、折射率以及波长光调谐等特性进行实验研究,从理论上证明该传感器的主动温度补偿的可行性,并在实验上实现了温度不敏感的折射率传感。论文最后系统地研究了高温再生光纤布拉格光栅,并在此基础上提出了一种新的高温光栅制作方法,即在高温下对再生光纤布拉格光栅进行粘弹性调谐时可以使用特定的温度分布来定制光栅的周期分布,永久地调谐出不同波长和带宽的高温光纤光栅。利用这一方法,在实验上将使用均匀周期相位掩模板制作的一个窄带均匀光栅,永久地调谐成宽带啁啾光栅,并且其中心波长和宽带任意可调。同时,利用再生光栅技术和粘弹性调谐技术,将使用均匀周期相位掩模板制作的含有三个相同波长的光纤光栅阵列,永久地调谐成三个不同波长的光纤光栅阵列,并且其波长间距任意可调,适用于准分布式高温传感。本论文理论和实验研究并重,研究新型光纤光栅传感技术和高温光纤光栅制作技术,对推动光纤光栅技术及其应用的发展具有良好的意义。更多还原

【Abstract】 Fiber gratings, as key passive fiber components, have a wide range of applications in optical fiber communication, optical fiber sensing and other fiber-optic technologies. The emergence of fiber gratings marks a technical milestone in the fiber-optic field. This thesis mainly focuses on the novel fiber grating sensing technology and the fabrication technique of high temperature fiber gratings. Comprehensive studies on these topics have been conducted both theoretically and experimentally.To begin with, a brief overview of the historical background of fiber and the development of fiber grating technology are given. The applications of fiber gratings in communication and sensing are introduced, and the classification of fiber grating sensing and its market prospect are discussed. The recent research topics on fiber grating sensing technology are also summarized.Then, a brief discussion on the photosensitivity of fiber is given. The basic theoretical analysis tools of fiber gratings, including diffraction theory, coupled-mode theory and transfer matrix method, are introduced. The classification of fiber grating is summarized and several typical kinds of fiber gratings are briefly introduced along with their typical spectra. Brief introduction on the fabrication techniques for fiber gratings, the hydrogen-loading setup and the fabrication system used in this thesis, is also given.After that, novel flow speed/rate sensing technology based on laser-heated fiber Bragg gratings (LHFBGs) is studied and developed. LHFBGs are novel components and have some special properties, e.g. photothermal conversion, laser-control wavelength tuning, which enable many unique applications. Based on analyzing the thermal distribution of the LHFBG and the hot-wire anemometry, LHFBG-based all-fiber air speed sensor and microfluidic flow rate sensor are proposed and experimentally demonstrated. By employing an FBG interrogator, the wavelength response, sensitivity and response time of these sensors are investigated in detail under different conditions, and high-resolution, high-sensitive flow speed/rate sensing is achieved.Furthermore, a fiber-optic refractive-index sensor based on laser-heated fiber long-period gratings (LHFLPGs) with active temperature compensation is proposed and experimentally demonstrated. Experimental investigation of the temperature sensitivity, refractive-index sensitivity and the wavelength tuning feature of the LHFLPGs, is well conducted. In theory, the proposed sensor is proved to be feasible, and temperature-insensitive refractive-index sensing is achieved experimentally.Finally, high temperature regenerated fiber Bragg gratings (RFBGs) are systematically studied. A novel fabrication technique for high temperature RFBGs is presented-during the viscoelastic tuning of the RFBG under high temperature, it is possible to employ a particular temperature profile to customize the profile of the grating period, enabling permanently tuned RFBGs with different wavelength and bandwidth. Using this technique, a narrowband uniform grating produced by uniform phase mask is permanently tuned into a broadband chirped grating, with arbitrary bandwidth and central wavelength. By employing the viscoelastic tuning technique, FBG array with three gratings with the same wavelength, is also permanently tuned into another FBG array with three different wavelengths, which is applicable to quasi-distributed high temperature sensing.In conclusion, novel fiber grating sensing technology and the fabrication technique of high temperature fiber gratings are investigated both theoretically and experimentally in this thesis, which would contribute to the development of the fiber grating technology and its applications.更多还原