基于频谱分区的高精度光纤布拉格光栅传感解调系统的研究

发布时间：2018-03-24 10:09

本文选题：光纤光学　切入点：光纤光栅传感解调系统　出处：《南京大学》2015年硕士论文

【摘要】：以光纤技术为基础发展起来的光纤无源及有源器件一直是全世界学者研究的重点,也是相关行业各公司新技术新产品的研发核心。光纤布拉格光栅便是其中一个典型的应用器件,它是一种可以将外界多种环境参量转换成光栅的布拉格反射中心波长信息变化量的器件。其优势在于有效避免了多种外界不稳定因素的影响,并降低了传统传感器使用时受到的电磁干扰,同时以其优异的低成本效应,被越来越多的行业探索使用。在传感解调系统中,最为关键的技术是如何准确并稳定的解调出布拉格反射波长变化以实现对外界环境参量的传感,这也是本文的研究重点。本文从基本的模式耦合原理入手,推导出光纤光栅的温度及应力传感模型,然后对比了现有解调方法的优劣势,选择使用目前应用最为广泛的光纤法布里-珀罗(Fabry-Perot)滤波法进行解调。但是由于光纤法布里-珀罗滤波器调谐时存在蠕动、磁滞和非线性特性,严重影响解调系统的精度与稳定性。为了解决该问题,本文结合光纤法布里-珀罗(Fabry-Perot)标准具提出了一种基于频谱分区的解调方案,使用标准具动态校准滤波器的波长读取值,很好的消除了由滤波器调谐的温漂和蠕动引起的测量误差；同时利用ASE光源特性进行频谱分区解调,大大降低了滤波器调谐时非线性的影响,使得解调系统具有很高的解调精度和很好的稳定性。为了实现系统的性能,设计与制作了以DSP2812为核心的高速硬件控制与采集电路,并结合LabVIEW和Matlab设计了计算机端的数据处理程序与整个系统的交互界面,丰富了系统功能,简化了操作难度。最后对该系统的性能进行了测试,并对系统可能存在的误差进行了分析,实验结果表明本文所设计的系统稳定性为0.97pm,分辨率达到了0.33pm,温度解调误差为0.03-0.13。C,线性度为0.9999,相对于传统滤波器法,本系统的温度解调精度和稳定性均得到了很大提升。验证了本系统能够应用到实际中进行温度的实时监控。
[Abstract]:Passive and active optical fiber devices developed on the basis of optical fiber technology have been the focus of scholars all over the world. It is also the core of the research and development of new technology and new products of companies in related industries. Fiber Bragg grating is one of the typical application devices. It is a kind of device which can convert a variety of environmental parameters from the outside to the Bragg reflection center wavelength information of grating. Its advantage is that it can effectively avoid the influence of many external instability factors. It also reduces the electromagnetic interference of traditional sensors and is used by more and more industries because of its excellent low cost effect. The key technology is how to demodulate the Bragg reflection wavelength change accurately and stably to realize the sensing of the external environment parameters, which is also the focus of this paper. The temperature and stress sensing models of fiber gratings are derived, and the advantages and disadvantages of the existing demodulation methods are compared. The most widely used fiber Fabry-Perot filtering method is chosen for demodulation. However, due to the peristaltic, hysteresis and nonlinear characteristics of fiber Fabry-Perot filter tuning, The precision and stability of demodulation system are seriously affected. In order to solve this problem, a demodulation scheme based on spectrum partition is proposed in this paper, which combines Fabry-Perot (Fabry-Perot) standard with fiber Fabry-Perot, and uses the standard wavelength to calibrate the wavelength of the filter dynamically. The measurement error caused by the temperature drift and creeping of filter tuning is eliminated well, and the frequency spectrum is demodulated by using the characteristic of ASE light source, which greatly reduces the nonlinear effect of filter tuning. The demodulation system has high demodulation precision and good stability. In order to realize the performance of the system, a high-speed hardware control and acquisition circuit based on DSP2812 is designed and fabricated. The interaction interface between the computer end data processing program and the whole system is designed by combining LabVIEW and Matlab, which enriches the system function and simplifies the operation difficulty. Finally, the performance of the system is tested. The experimental results show that the system stability is 0.97 pm, the resolution is 0.33 pm, the temperature demodulation error is 0.03-0.13.C, and the linearity is 0.9999, compared with the traditional filter method. The temperature demodulation accuracy and stability of the system have been greatly improved, and it is verified that the system can be applied to the real time temperature monitoring.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP212;TN713

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