基于AWG的多通道光纤布拉格光栅传感解调系统的研究

【作者】 孙杰；

【导师】 李鸿强； 薛京生；

【作者基本信息】 天津工业大学 ， 电子与通信工程（专业学位）， 2016， 硕士

【摘要】 光纤布拉格光栅(Fiber Bragg Grating,FBG)传感器是一种新型的光无源器件,在抗电磁干扰、轻巧、灵敏度、耐腐蚀性等方面具有独特的优势。近年来,随着FBG传感检测技术的发展,FBG传感器已广泛地应用到航空航天、石油化工、电力系统、土木工程、生物化学以及医学等领域。当前,在一些大型工程及结构监测中往往需要大量的传感器,比如对大型建筑物结构的监测可能需要几百上千个传感器,单点FBG传感技术已无法满足实际需求,因此国内外学者对分布式光纤光栅传感解调技术进行了深入的研究,并已提出了多种分布式光纤光栅传感解调方案,但主要以有源解调方法为主,该方法采用单一波长在传感光谱范围内对波长进行扫描,将传感光信号按波长依次进行光电转换,因而在解调速度、响应速度、光谱资源利用率等方面都不能令人满意,因此有必要开发一种高响应度、高精度和成本适中的分布式多通道光纤光栅解调系统。本文对多通道分布式FBG传感网络的波长解调技术进行了深入的研究,在详细分析各种常见的光纤布拉格光栅波长解调技术优缺点的基础上,设计开发了一种基于阵列波导光栅(Arrayed Waveguide grating,AWG)的多通道光纤布拉格光栅传感解调系统。该系统由宽带光源、光隔离器、光耦合器、光环路器、FBG传感器、AWG、光电转换电路、调理放大电路、低通滤波电路、A/D转换电路、ARM控制电路以及上位机监测软件等组成,采用光强法对FBG传感器波长偏移量进行解调,系统采用STM32F107作为系统的控制芯片,高速8通道ADS8345作为信号采集芯片,实现多通道传感数据的采集,使用LabVIEW2014软件编写人机交互界面,通过串口实现上位机与下位机之间的数据交换,完成多通道数据同时采集、解调、显示及存储功能。实验中对单通道8个FBG传感实验进行了测试,实验结果表明,该解调系统的各通道采样频率为1KHz,波长解调范围为1545.30～1560.50nm,温度测量误差为±0.3℃,波长解调精度为±3pm,波长分辨率为1pm。若需实现对更多FBG传感器的测量,可通过扩展通道板的数量来实现多通道的测量。更多还原

【Abstract】 Fiber Bragg Grating (FBG) sensor is a new kind of optical passive components, it has unique advantages such anti-electromagnetic interference capability, light, corrosion resistance, high detection sensitivity and so on. Recently, the development of sensor detection technology is becoming mature gradually based on FBG. The FBG sensor has been widely used in the field of spacecraft industry, petrochemical, power electronics, civil engineering structures, biological chemistry and medical fields and so on. Currently, a large number of sensors are needed for structural monitoring and controlling in large-scale projects. For example thousands of sensors are necessary to monitor the large building structure. Therefore single FBG sensor can not fulfill these practical needs. Now domestic and foreign scholars began to pay more attention to the distributed FBG sensor system. A variety of distributed fiber Bragg grating sensing demodulation schemes has been proposed. However these schemes are mostly based on active demodulation technologies. In these methods, the wavelength of light is scanned by a single wavelength in the range of sensing spectrum and the optical signal is converted to electrical signal followed by wavelength. It can not be satisfactory in terms of demodulation rate, response speed, spectrum resource utilization. So it is necessary to develop a distributed multi-channel FBG demodulation system with high responsive, high accuracy and moderate cost.In this thesis, the wavelength demodulation technology of multi channel distributed FBG sensing network has been studied deeply. On the basis of analyzing the advantages and disadvantages of several common FBG demodulation methods, this paper proposes a multi-channel FBG sensor demodulation system based on Arrayed Waveguide Grating (AWG). This system consists of a broadband light source, isolator, optical coupler, circulator, FBG sensors, AWG, photoelectric detection circuit, amplifying circuit, low pass filter circuit, AD sampling circuit, ARM control circuit and PC monitoring software, etc. By the method of the strength, the temperature of the FBG sensor is demodulated. The STM32F107 is used as the control chip and the high-speed 8 channel ADS8345 is used to sample the real-time signal in this system. The multi-channel sensing data can be collected by the method of selecting ADS8345 chip in a poll mode. The main interactive mode software is completed based on LabVIEW2014, which achieves the function of the display, storage and analysis. Experiment has been carried out to test the single channel 8 FBG sensors. The experiment results show that the sampling rate is 1 KHz for each channel, the range of wavelength demodulation is 1545.30-1560.50nm, the demodulation error is not more than ±0.3℃, the precision of wavelength demodulation is ±3pm and the wavelength resolution is 1pm. By extending the number of channel plate can realize more FBG sensor measurement.更多还原