可调谐DFB激光器动态扫描的FBG解调系统研究

发布时间：2018-01-07 04:25

本文关键词：可调谐DFB激光器动态扫描的FBG解调系统研究　出处：《哈尔滨理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：光纤布拉格光栅（FBG）传感器以其独有的波长编码和易构成准分布式传感网络的特性，受到广泛的关注和应用。但现有的FBG传感解调方法大部分是将波长转化为强度、相位等其它物理量来测量，受传输损耗和光功率波动等因素影响严重，而直接波长解调的系统则较少，还存在集成度不高、价格昂贵等问题，，阻碍了FBG在实际工程中的应用。因此，本文建立了一套FBG直接波长解调系统，该系统具有便于集成、成本低、稳定性好等优点，能够满足实际应用的需要。首先，本论文基于FBG传感器的基本工作原理，利用分布式反馈（DFB）激光器的波长调谐特性与固定Fabry-Perot标准具的波长选择特性，设计了一种基于可调谐DFB激光器动态扫描的FBG波长解调系统方案，并从理论上说明了该方案的原理以及可行性。然后，在理论研究的基础上，搭建了基于可调谐DFB激光器动态扫描的FBG波长解调系统的实验平台，重点研究了可调谐DFB激光器的波长扫描特性与固定Fabry-Perot标准具的特定波长透射特性，研究发现：由于DFB激光器并非是理想地线性波长扫描，导致输出峰值间隔不等的Fabry-Perot标准具透射谱，而利用二次多项式拟合波长与扫描时间点的拟合度达到0.999以上。同时，针对FBG与Fabry-Perot标准具的光谱特点，研究了现有的寻峰算法，提出先直接寻峰后高斯拟合的方法来处理FBG与Fabry-Perot标准具的时域信号，结合二项式拟合算法，建立了该系统的完整解调算法；并采用C语言和LabVIEW联合编程的方式，编写出该系统的数据处理程序，对由实验平台采集到的时域信号进行数据读取、算法处理、结果显示，该程序具有便于操作的交互式数据处理界面，且易于后续的开发与优化。最后，经过标定试验的研究得出，该系统的分辨率为1pm、测量精度为±10pm、测量范围为1547~1552nm、相对误差为0.26%，符合FBG应用的行业标准。
[Abstract]:Fiber Bragg grating (FBG) sensor is characterized by its unique wavelength coding and easy to form a quasi-distributed sensor network. However, most of the existing demodulation methods of FBG sensor are measured by conversion of wavelength to intensity, phase and other physical quantities, which are seriously affected by transmission loss and optical power fluctuation. However, the direct wavelength demodulation system has few problems, such as low integration, high price and so on, which hinders the application of FBG in practical engineering. Therefore, a set of FBG direct wavelength demodulation system is established in this paper. The system has the advantages of easy integration, low cost, good stability and can meet the needs of practical applications. Firstly, based on the basic principle of FBG sensor, the wavelength tuning characteristics of distributed feedback FBG laser and the wavelength selection characteristics of fixed Fabry-Perot standard are used in this paper. A scheme of FBG wavelength demodulation system based on dynamic scanning of tunable DFB laser is designed, and the principle and feasibility of the scheme are explained theoretically. Then, on the basis of theoretical research. The experimental platform of FBG wavelength demodulation system based on dynamic scanning of tunable DFB laser is built. The wavelength scanning characteristics of tunable DFB lasers and the specific wavelength transmission characteristics of fixed Fabry-Perot standard devices are mainly studied. It is found that because DFB laser is not an ideal linear wavelength scanning, Fabry-Perot standard with different output peak interval has transmission spectrum. The fitting degree of wavelength and scanning time point by quadratic polynomial is more than 0.999. At the same time, the spectral characteristics of FBG and Fabry-Perot standard are analyzed. In this paper, the existing peak finding algorithm is studied, and a direct peak searching and Gao Si fitting method is proposed to deal with the time domain signals of FBG and Fabry-Perot standard, combined with binomial fitting algorithm. The complete demodulation algorithm of the system is established. The data processing program of the system is written by using C language and LabVIEW, and the time domain signal collected by the experiment platform is read, processed by algorithm, and the result is displayed. The program has an interactive data processing interface which is easy to operate, and is easy to be developed and optimized. Finally, the resolution of the system is 1 pm and the measurement accuracy is 卤10 pm. The range of measurement is 1547 ~ 1552 nm and the relative error is 0.26, which conforms to the industry standard of FBG application.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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