基于衍射解调的新型光纤光栅高温传感网络

基于光纤布拉格光栅(FBG)高温传感特性,设计了一种基于波长调制的耐高温光纤光栅传感网络。系统设计了新型封装结构的耐高温光栅传感头。并针对传统FBG传感网络结构可靠性低的缺点,设计了一种高可靠分布式传感网络结构。采用InGaAs图像传感衍射解调技术对光反射波长进行解调。20～290℃范围测试实验表明,所设计的传感网络温度响应曲线平均线性度达0.9991,灵敏度为0.0258nm/℃,测量精度达±0.6℃,响应时间小于16s,稳定性高,适用于实际工作环境中的高温测量。     

High-Frequency Fiber Bragg Grating Sensing Interrogation System Using Sagnac-Loop-Based Microwave Photonic Filtering

A novel high-frequency fiber Bragg grating (FBG) sensing interrogation system by using fiber Sagnac-loop-based microwave photonic filtering is proposed and experimentally demonstrated. By adopting the microwave photonic filtering, the wavelength shift of sensing FBG can be converted into amplitude variation of the modulated electronic radio-frequency (RF) signal. In the experiment, the strain applied onto the sensing FBG has been demodulated by measuring the intensity of the recovered RF signal, and by modulating the RF signal with different frequencies, different interrogation sensitivities can be achieved.      

基于光频域反射的总线型拓扑结构FBG传感网络

为了提高光纤光栅(FBG)传感系统的传感容量以及传感器的实际工程生存能力和后期可维护性,提出了一种基于光频域反射(OFDR)技术的总线型拓扑结构的FBG传感系统。利用OFDR技术,采用相同波长的FBG传感器,克服了光源带宽对系统传感容量的限制,极大提高了系统的传感器复用能力和空间分辨率。与传统的采用弱反射率FBG串联组网相比,本文系统采用强反射率FBG和光分路器实现总线型拓扑结构,在提高传感器的生存能力的同时,克服了串接式FBG传感网络中存在的多重反射和光谱阴影对测量精度的影响。温度实验表明,系统的波长重复性为±4pm。     

Ultra-Long-Distance Fiber Bragg Grating Sensor System

A long-distance fiber Bragg grating (FBG) sensor system has been developed using a wavelength-swept light source with output power turned on-off and timing synchronized to the sweep signal to reduce optical noise caused by Rayleigh scattering generated from the transmission fiber. This system can detect changes in the FBG reflection wavelengths even if the FBG is 120 km from the sensing position.     

光纤光栅埋入后温度、应变解耦分析

光纤光栅传感器在现实应用中的一个主要问题是温度和应变的交叉敏感问题.介绍了光纤双光栅同步测量温度和应变的原理,设计了一个光纤双光栅温度、应变测量系统,对光纤双光栅的温度和应变传感性能进行了实验研究,结果表明光纤双光栅具有多参量同时测量的能力.     

A Novel Temperature-Compensated,IntensityModulated Fiber Bragg Grating Sensor System

An intensity-modulated, fiber Bragg grating (FBG) sensor system based on radio-frequency (RF) signal measurement is presented. The RF signal is generated at a photodetector by two modulated optical signals reflected from the sensing FBG and a reference one. Bragg wavelength shift of the sensing FBG changes intensity of the RF signal by changing phase difference between the two optical signals, with temperature effect being compensated automatically by the reference FBG. Strain measurement with a maximum sensitivity of -0.34 V/ has been achieved.     

基于REC技术的激光器阵列传感系统设计

分析并提出了基于重构等效啾啁（REC）技术激光器阵列的传感系统和解调算法。REC工艺满足激光器阵列的低成本大量生产,并具备小体积的优势,在未来传感领域中有较大的实用价值。提出了一种激光器扫描的高效算法用来测量光纤布拉格光栅（FBG）因外界应力而产生的位移量。系统的独特性在于阵列激光器通道仅需调谐0.4 nm采样数据,取代了扫描FBG主功率峰,并且算法在FBG的任意谱段均适用,可以用于多通道波峰复用的FBG传感网络中。在单通道和四通道的实验中对FBG反射谱的位移进行精确定位,初步实验证明了该系统和算法的有效性和可行性。算法得出单通道中心波长与实际中心波长误差均在5 pm以下,四通道可以到达在2 pm以下,应力与算法结果中心波长呈现很好的线性度。对今后多通道激光阵列传感具有一定参考价值。     

光纤光栅在液氮温区温度传感性能的研究

文章从光纤光栅的温度传感模型出发,理论分析了光纤光栅的温度传感特性,完成了在液氮温区(-196 ℃)的温度测量.将理论与实验结果进行对比分析后得知,在液氮温区或者大范围测温中,反射波长相对漂移量ΔλB/λB与温度改变量ΔT的关系是非线性的,呈二次关系式.     

A Novel Temperature-Compensated, Intensity-Modulated Fiber Bragg Grating Sensor System

An intensity-modulated, fiber Bragg grating （FBG） sensor system based on radio-frequency （RF） signal measurement is presented. The RF signal is generated at a photodetector by two modulated optical signals reflected from the sensing FBG and a reference one. Bragg wavelength shift of the sensing FBG changes intensity of the RF signal by changing phase difference between the two optical signals, with temperature effect being compensated automatically by the reference FBG, Strain measurement with a maximum sensitivity of -0.34 μV/με has been achieved.     

光纤光栅传感系统的信号解调

首先介绍了光纤光栅的基本知识,再分别介绍了几种典型解调方法的工作原理、性能和特点,给出了其工作原理图,并对各种解调方法的优缺点进行了论述。提出了一种基于CCD的光纤光栅传感解调系统,该系统采用反射式成像系统,用CCD作为探测器,并利用可编程逻辑器件FPGA设计驱动电路和信号处理电路,实现了一种体积小、结构简单,解调速度快,可以实时测量的波长解调系统,为光纤光栅解调技术的实际应用和光纤光栅传感解调系统的设计提供了理论依据。     

Fire Detection Method Based on Identical Fiber Bragg Grating

Wavelength division multiplex has obvious advantages when it is used in fiber Bragg grating （FBG） sensing for simultaneous measurement of various quantities, but the number of sensors is usually restricted by the bandwidth of SLED and demodulator. The identical fiber Bragg grating is introduced for fire alarm system and the method of collecting signal of identical FBG sensors is described. The experiment result shows that with identical FBG sensing. The number of the sensors coupled in one fiber increases greatly and the precision can be ensured to meet the requirement for fire alarm system.     

FBG传感器在巷道掘进中的应用研究

采用光纤Bragg光栅（FBG）传感器监测了巷道模型的掘进过程。利用FLA^3D软件对巷道模型进行了掘进过程的应力分析,根据应力分布情况在巷道模型中布设了15个三维应变FBG传感器和3个温度FBG传感器,通过四通道SM125解调仪对传感信号进行系统解调以及数据存储。该传感系统测量精度高,检测的应力变化与FLAC^3D软件模拟结果吻合性好,表明FBG传感器在土木工程的监测中有较好的应用前景。     

基于线型腔拉曼光纤激光器的长距离光纤布拉格光栅传感

提出了一种基于线型腔拉曼光纤激光器的长距离分布式光纤布拉格光栅(FBG)传感解调系统,并进行了理论分析和实验验证。传感光纤布拉格光栅构成拉曼光纤激光器腔镜的一端,受一维调节器调节控制的匹配光纤布拉格光栅构成腔镜的另一端。一维调节器与步进电机相连,步进电机由计算机(PC)通过可编程逻辑控制器(PLC)进行控制,一维调节器通过调节匹配光纤布拉格光栅的周期来控制激光器的输出。实验结果表明,传感解调系统能很好地实现长距离分布式传感及传感信号的检测。30 km非归零色散位移光纤(NZDSF)用于拉曼增益可以产生信噪比大于40 dB的稳定拉曼激光输出,在4.2 nm范围内系统解调精度为0.05 nm。     

基于单片机实现的光纤光栅应力传感器

提出了一种用单片机控制光介质薄膜干涉滤波器探测光纤光栅波长偏移量的方法,并 构建了对外界应力实时检测的光纤光栅应力传感系统。实验中采用了一种超磁致伸缩材料(GMM) ,使光纤布拉格光栅( FBG)产生有效的B ragg波长偏移,用控制电流来调控FBG的应变和Bragg波长偏移;电流加到1A～5A之间时,反射峰的中心波长的偏移量随所加电流呈线性增加的趋势,偏移量达到1. 10nm ( 1551. 94nm～1553. 04nm) 。该系统具有对应力测量结果分辨率高、精度高等优点。     

新型耐高温FBG传感系统研究

为解决传统的高温传感器不能满足对电解Al槽温等高温环境的实时在线测量问题,提出了基于波长调制的光纤Bragg光栅（FBG）高温传感系统,设计了一种新型封装结构的耐高温FBG传感头,具有体积小、灵敏度高和线性度好等特点;采用了基于InGaAs图像传感器衍射解调技术对光反射波长进行解调,缩短了系统的响应时间,提高了测量精度...     

Ultra-long-distance fbg sensor system based on spectrum-limited fourier domain modelocking fibre laser with raman pumps

A novel ultra-long-distance (up to 76 km) fibre Bragg grating (FBG) sensor system based on a spectrum-limited Fourier domain modelocking fibre laser is proposed. Raman pumps are employed to form a Raman amplifier to compensate the transmission loss of the long fibre and ensure ultra-long-distance sensing. Strain sensing based on such an ultra-long-distance FBG sensor system is demonstrated with a signal-to-noise ratio over 22 dB and a sensitivity of 1.03 pm/muepsiv in the wavelength domain or 18.3 ns/muepsiv in the time domain.     

Lab VIEW实现光纤光栅传感干涉解调技术的研究

结合虚拟仪器技术和光纤光栅传感技术,自行设计了一套光纤光栅传感解调系统.系统采用了基于迈克尔逊干涉技术的解调方法,将包含被测应变信息的FBG波长信号转变成相位信号,通过以Lab VIEW为核心的虚拟仪器系统检测相位的变化,从而得到被测应变的大小.该干涉解调系统避开了传统解调系统受电磁干扰和环境等方面的影响,因此使得测量精度有了很大的提高.虚拟仪器系统可用于静态应变和动态应变的检测,具有高分辨力、大测量范围的特点.     

基于波分复用的光纤多防区周界传感系统

提出了一种新的光纤多防区周界传感系统,采用波分复用技术实现了监控防区和通道的扩展。该系统对传统采用单根传感光纤和反射镜的结构作了改进,并扩展了传感光纤的数量,将多根传感光纤分别置于监控领域内的不同防区,每个防区分别用不同中心波长的光纤布拉格光栅作为反射装置,使每根传感光纤工作在不同的波长。利用波分复用器件与技术,多根传感光纤共用一套干涉系统,实现了多个干涉子系统同时、独立的监测。实验结果表明,该系统可以实现多个分散防区同时、独立的入侵检测和定位,信号响应时间小于1ms,不同防区间信号的串扰小于-20dB。     

Sagnac fiber interferometer with the population grating for fiber Bragg grating dynamic strain sensing

A Sagnac fiber interferometer with the population grating formed in saturable erbium-doped fiber (EDF) for fiber Bragg grating (FBG) dynamic strain sensing is proposed. In this configuration, a semiconductor optical amplifier (SOA)-based fiber ring laser with an FBG reflector is employed in the sensing part and a Sagnac interferometer based on transient two-wave mixing (TWM) via dynamic population gratings in single-mode polarization maintaining erbium-doped fiber (PM-EDF) is used in this detecting part. Experimental results show that the Sagnac fiber interferometer detection system can stably respond to dynamic strains at high frequencies. As an example of application, the response of the sensor system to continuous sinusoidal ultrasonic signals is presented. The proposed simple and robust configuration has an all-fiber design based on commercially available elements, which makes it promising for applications in fiber optic ultrasonic sensors.     

FBG传感技术在智能车流量检测系统中的应用

探讨了光纤布拉格光栅（FBG）传感技术在公路交通流量检测监视系统中的应用和FBG应力传感中温度交叉敏感的问题.首先从理论上分析了光纤光栅传感器的结构和原理,然后通过实验研究并搭建实验系统,经反复测试最终取得了理想的实验结果.利用不同车型的数次过车实验,证明该识别系统识别准确率达100%,且该系统不怕潮湿、粉尘、抗电磁干扰,有望替代现有的电类产品,在工程实践中获得广泛应用.