基于长周期光纤光栅的压力传感研究

发布时间：2018-05-11 22:15

本文选题：光纤光栅 + 长周期光纤光栅　；参考：《深圳大学》2015年硕士论文

【摘要】：光纤光栅是一种使用一定方法使光纤纤芯的折射率在轴向上周期性变化而形成的衍射光栅,具有体积小、波长可选择、不受非线性效应影响、抗电磁干扰能力强、同光纤通信系统连接损耗低等优点。在光纤通信和光纤传感领域受到极大的关注,成为光纤领域的研究热点。很多工业自控环境,如水利水位、石化管道、油井以及气体管道压力等,都需要长期实时的压力测试,将长周期光纤光栅应用于压力传感方面的研究正在不断深入之中。本文以感生式长周期光纤光栅为压力传感元件,提出了一种感生长周期光纤光栅和普通长周期光纤光栅相级联的结构,该结构利用干涉原理,可大大提高压力传感的灵敏度。本论文主要完成了以下方面的研究工作并取得了若干创新性的成果。首先介绍了光纤光栅的分类以及相应光谱特性,总结了光纤光栅在通信和传感中的应用。其次从麦克斯韦方程组入手,详细介绍了光纤光栅的模式耦合理论,从理论上解释了光纤光栅模式耦合的原因。对长周期光纤光栅的模式耦合理论进行了推导,利用软件对长周期光纤光栅的输出光谱进行了仿真。然后概括介绍了长周期光纤光栅的多种制作方法,包括相位掩模法、振幅掩模法、紫外逐点写入法、腐蚀刻槽法、机械感生写入法等,并对它们的优缺点进行了比较分析。另外,还详细地介绍了紫外激光制作长周期光纤光栅的系统搭建,包括光路搭建、光路准直等。特别要指出的是该系统实现了光纤光栅制作过程中准分子激光器和一维电控平移台的一体化控制,开发了集成控制软件。在软件中可灵活设置制作相关参数,实现不同种类光纤光栅的制作,大大提高了制作效率。此外,还对机械感生写入长周期光纤光栅的方法进行了研究,提出了一种新型的机械感生压模模板,可灵活改变光栅长度、微量改变光栅周期。最后对机械感生长周期光纤光栅进行压力传感研究,创新地提出感生长周期光纤光栅和普通长周期光纤光栅相级联构成M-Z干涉仪的结构,详细分析了它的光谱特性,研究了谐振情况下的压力传感,发现这种由感生长周期光纤光栅和普通长周期光纤光栅相级联构成的传感器使传感灵敏度大大提高。
[Abstract]:Fiber Bragg grating (FBG) is a kind of diffractive grating formed by using certain method to make the refractive index of fiber core change periodically in the axial direction. It has the advantages of small volume, optional wavelength, no influence of nonlinear effect, and strong ability of resisting electromagnetic interference. Low connection loss with optical fiber communication system. In the field of optical fiber communication and optical fiber sensing, it has become a research hotspot in the field of optical fiber. Many industrial automatic control environments, such as water level, petrochemical pipelines, oil wells and gas pipeline pressure, need long-term real-time pressure testing, and the application of long-period fiber Bragg grating in pressure sensing is being deeply studied. In this paper, a kind of phase cascade structure of sensing growth period fiber grating and ordinary long period fiber grating is proposed, in which the inductive long period fiber grating is used as the pressure sensor element. The structure can greatly improve the sensitivity of pressure sensing by using the principle of interference. In this paper, the following research work has been completed and some innovative results have been achieved. Firstly, the classification and spectral characteristics of fiber gratings are introduced, and the applications of fiber gratings in communication and sensing are summarized. Secondly, starting with Maxwell's equations, the mode coupling theory of fiber grating is introduced in detail, and the reason of mode coupling of fiber grating is explained theoretically. The mode coupling theory of long period fiber grating is deduced, and the output spectrum of long period fiber grating is simulated by software. Then several fabrication methods of long period fiber grating are introduced, including phase mask method, amplitude mask method, ultraviolet point-by-point writing method, etching grooving method, mechanically induced writing method, and their advantages and disadvantages are compared and analyzed. In addition, the system construction of long period fiber grating fabricated by UV laser is introduced in detail, including optical path construction, optical path collimation and so on. In particular, it is pointed out that the system realizes the integrated control of excimer laser and one-dimensional electrically controlled translation platform during the fabrication of fiber Bragg gratings, and the integrated control software is developed. In the software, the relevant parameters can be flexibly set to realize the fabrication of different kinds of fiber Bragg gratings, which greatly improves the production efficiency. In addition, the method of mechanically induced writing long period fiber gratings is studied, and a new type of mechanically induced compression mode template is proposed, which can flexibly change the grating length and slightly change the grating period. Finally, the pressure sensing of the mechanically induced growth period fiber grating is studied, and the structure of M-Z interferometer is proposed, which is composed of the phase cascade of the fiber grating and the ordinary long period fiber grating, and the spectral characteristics of M-Z interferometer are analyzed in detail. The pressure sensing under resonant condition is studied. It is found that the sensing sensitivity is greatly improved by this sensor which consists of the cascaded growth period fiber grating (FBG) and the common long-period fiber grating (LPFG).
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253

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