基于F-P腔滤波器的FBG温度传感器解调技术

近些年来,光纤光栅传感器成了传感领域的研究热点.对高精度的波长编码信号解调是实现光纤光栅传感的关键技术.介绍了光纤布拉格光栅(FBG)传感器的工作原理,同时对F-P腔滤波器的工作原理进行了分析,阐述了光纤光栅传感器解调技术的发展趋势,并提出了光纤光栅传感器解调技术需要解决的技术问题.     

基于光纤光栅的传动齿轮模态分析

利用光纤光栅传感器实现了基于快速应变响应的传动齿轮模态分析。基于波分复用技术组建光纤光栅传感网络,根据光纤光栅的应变响应数据完成齿轮的应变模态分析,并与基于声压传感器的齿轮试验模态分析结果进行对比,固有频率相对误差小于0.1%。为了实现光纤光栅传感器的快速应变采集,搭建了一套光纤光栅快速解调仪。该解调仪是基于体相位解调的单通道快速解调仪,采样速率最高为35kHz,使用LabVIEW编写了光纤光栅信号采集和解调软件。基于光纤光栅的齿轮应变模态分析方法附加质量小,比传统加速度传感器测量结果更准确,能够适应小型齿轮箱内部复杂和恶劣的测量环境,具有一定的应用价值。     

用于周界安防的光纤光栅振动传感系统研究

基于光纤光栅传感理论设计了一种应用于周界安防的低频振动传感器.采用商用解调仪OPD4000对传感器的灵敏度进行了测试,在10～100 Hz频率范围内,传感器灵敏度高于1 000 pm/g.基于非平衡迈克尔逊干涉仪相位载波调制(PGC)解调技术搭建了一套光栅传感器解调系统,实现对传感器低频振动信号的高精度实时解调,使得该系统可广泛应用于机场、监狱、油库、核场所等重要区域的周界安防中.     

光纤光栅动态称重技术的研究

在实验室内搭建了一套光纤动态称重系统,该系统是基于普通单模光纤光栅传感技术。在实验小车经过支撑称重台面的金属弹性体时,将引起弹性体形变,采用光纤光栅传感器监测这一形变。通过分析光纤光栅解调仪采集到的光纤光栅传感信号,反演出实验小车的质量。实验结果表明系统精度优于±3%。该系统采用实时校准光纤光栅传感器基准传感波长方法,消除了环境温度对测量结果的影响,具有自温度补偿功能。     

一种新型的光纤光栅金属腐蚀传感器

介绍一种新型的基于光纤光栅应变传感特性的金属腐蚀传感器。实验中,传感器被放置在腐蚀液中,并使用MOI SM125波长解调仪监测光纤光栅反射谱中心波长。加速腐蚀实验持续大约7 h,结束时应变片被腐蚀的厚度为1.2 mm,光栅反射谱中心波长偏移了约4 nm。实验结果证明了该传感器设计的合理性和在实际应用中的可能性,同时也讨论将该种传感器投入实用所需要进行的改进。     

光纤光栅应变传感系统在船舶结构监测中的应用

介绍了一种光纤光栅应变传感系统在船舶结构监测中的应用.首先设计了贴片式的光纤光栅应变传感器,采用无胶化封装,具有良好的线性和重复性.然后搭建了基于非平衡M-Z干涉仪的PGC解调系统,实现了船体应变信号的高精度实时解调.最后介绍了传感器的施工工艺和流程,并对传感系统采集到的结构应变数据进行了分析.研究成果对光纤光栅应变传感系统在船舶结构监测中的推广应用具有工程指导意义.     

光纤光栅传感器的解调技术进展

阐述了光纤光栅传感器解调技术住近年来的发展情况,简要说明了光纤光栅传感的基本原理,并分别讨论了光纤光栅传感器的几种解调技术的特点以及实验装置．     

基于FPGA的光纤光栅解调系统的研究

波长信号的解调是实现光纤光栅传感网络的关键,基于现有的光纤光栅传感器解调方法,提出一种基于FPGA的双匹配光纤光栅解调方法,此系统是一种高速率、高精度、低成本的解调系统,并且通过引入双匹配光栅有效地克服了双值问题同时扩大了检测范围.分析了光纤光栅的测温原理并给出了该方案软硬件设计,综合考虑系统的解调精度和FPGA的处理速度给出了基于拉格朗日的曲线拟合算法.     

基于匹配滤波解调的光纤光栅振动传感器设计

为了弥补现有振动传感器的不足,在分析匹配光栅解调原理的基础上,设计了一种新型的光纤光栅振动传感器.该传感器采用了梁式结构,可以通过调节梁改变传感光栅的中心波长和传感器的固有频率,既可以实现匹配解调,又扩大了频率测量范围.通过标准信号测试实验,得出该光纤光栅振动传感器具有良好的频率检测性能,频率测量范围为0～200 Hz,在20 Hz、190 Hz检测的波形具有良好的信噪比.     

光纤光栅传感器的波长解调技术研究进展

光纤布喇格光栅(Fiber Bragg grating,简称光纤光栅:FBG)波长的解调是光纤光栅传感器应用的关键技术之一.在简单介绍光纤光栅传感原理的基础上,综述了近年来国内外多种光纤光栅波长解调系统的工作原理,分析了相应解调方法的优缺点,讨论了当前光纤光栅波长解调存在的技术难点,展望了其未来的研究方向.     

一种跨海大桥的5G覆盖方案及效果分析

跨海大桥因天线和设备安装困难,一直是移动通信无线覆盖的难题。本文通过东海大桥5G覆盖案例,介绍了一种可行的跨海大桥5G覆盖解决方案,并结合实测数据对覆盖效果进行了分析,讨论了桥面覆盖这一特殊场景下的网络瓶颈和性能提升建议。     

Hybrid Interrogation System for Distributed Fiber Strain Sensors and Point Temperature Sensors Based on Pulse Correlation and FBGs

A hybrid interrogation scheme for distributed strain sensors and point temperature sensors is proposed and its feasibility is demonstrated. It exploits the advantages of distributed sensors and point sensors simultaneously. The proposed interrogation scheme uses a wavelength tunable pulse source and wavelength-dependent reflectors for region selective sensing. Experimental results confirm its linear response and a resolution of 0.02% of the total dynamic range, which in our experiment is over 2000 microstrains for sensing regions of around a 0.5-m length. The stability of the measurements is over 99.8%. Finally, the high input power from the signal source and the limited losses from the reflectors allow the usage of a large number of sensors in a fiber.      

Review of fiber Bragg grating sensor technology

The current status of the fiber Bragg grating (FBG) sensor technology was reviewed. Owing to their salient advantages, including immunity to electromagnetic interference, lightweight, compact size, high sensitivity,large operation bandwidth, and ideal multiplexing capability, FBG sensors have attracted considerable interest in the past three decades. Among these sensing physical quantities, temperature and strain are the most widely investigated ones. In this paper, the sensing principle of FBG sensors was briefly introduced first. Then, we reviewed the status of research and applications of FBG sensors. As very important for industrial applications,multiplexing and networking of FBG sensors had been introduced briefly. Moreover, as a key technology, the wavelength interrogation methods were also reviewed carefully. Finally, we analyzed the problems encountered in engineering applications and gave a general review on the development of interrogation methods of FBG sensor.     

A New Fiber-Bragg-Grating Sensor Interrogation System Deploying Free-Spectral-Range-Matching Scheme With High Precision and Fast Detection Rate

A new method for fiber-Bragg-grating sensor interrogation and multiplexing is proposed and its operating features are investigated experimentally. This technique utilizes free-spectral-range-matched interrogation (FSRMI) employing a tunable scanning Fabry-Perot filter and a multichannel bandpass filter. An -channel FSRMI allows simultaneous scanning and thus improvement of detection speed by times compared to a nonfree-spectral-range-matched interrogation scheme. A 5-pm wavelength resolution has been obtained. This technique simultaneously scans the multiple transmission peaks and provides solutions to a wavelength-modulated distributed sensors and multisensor arrays with high sampling speed and wavelength accuracy.     

Design of an optical system for interrogation of implanted luminescent sensors and verification with silicone skin phantoms

Implantable luminescent sensors are being developed for on-demand monitoring of blood glucose levels. For these sensors to be deployed in vivo, a matched external hardware system is needed. In this paper, we designed a compact, low-cost optical system with highly efficient photon delivery and collection using advanced optical modeling software. Compared to interrogation with a fiber bundle, the new system was predicted to improve interrogation efficiency by a factor of 200 for native sensors; an improvement of 37?times was predicted for sensors implanted at a depth of 1?mm in a skin-simulating phantom. A physical prototype was tested using silicone-based skin phantoms developed specifically to mimic the scattering and absorbing properties of human skin. The experimental evaluations revealed that the prototype device performed in agreement with expectations from simulation results, resulting in an overall improvement of over 2000?times. This efficient system enables use of a low-cost commercial spectrometer for recording sensor emission, which was not possible using only fiber optic delivery and collection, and will be used as a tool for in vivo studies with animal models or human subjects.     

Utilization of Extrinsic Fabry-Perot Interferometers with Spectral Interferometric Interrogation for Microdisplacement Measurement

The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers (EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noise-compensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.     

Spectral signal processing in intrinsic interferometric sensorsbased on birefringent polarization-maintaining optical fibers

The straightforward spectral signal processing technique is applied in intrinsic strain, temperature and distributed linear position interferometric fiber optic sensors based on birefringent polarization maintaining fibers. The method provides nonincremental absolute measurements of external physical parameter affecting the sensing fiber. Simultaneous interrogation of sensors in a network is demonstrated     

Matched-filter interrogation technique for fibre Bragg gratingarrays

A technique for the demodulation of fibre Bragg grating (FBG) sensor arrays that uses a matched grating array to optically filter and track wavelength shifts from the FBG sensors is demonstrated. The use of matched grating arrays in the serial configuration represents an efficient and potentially low-cost interrogation technique for FBG sensors     

长周期光纤光栅传感信号解调技术研究现状

长周期光纤光栅(LPFG)对温度、应变、液体浓度等外界环境变化的敏感度要远高于光纤布拉格光栅(FBG),在传感领域具有广泛的应用前景。然而LPFG的传感信号解调技术尚不成熟,大大制约了LPFG在传感领域的应用。针对现有LPFG传感信号的解调方法进行分析与评述,着重介绍了基于边沿滤波技术、法布里-珀罗(F-P)腔扫描滤波技术和阵列波导光栅(AWG)技术的几种解调方案,并对各个方案在解调精度、速度、成本等方面进行了比较与分析。此外,介绍了实现LPFG复用解调的方法,并在总结已有技术优缺点的基础上对LPFG信号解调技术的发展趋势进行了展望。     

Application of Multimode Laser Diodes in the Interrogation of Fiber Bragg Grating Sensors

The interrogation of fiber Bragg grating sensors with multimode laser diodes is theoretically and experimentally analyzed using two different approaches: serrodyne and dithering techniques. It is also demonstrated that by using several laser modes it is possible to enhance the measurement range without compromising sensitivity.