一种用于大型发电机的新型光纤传感器的研究

利用光纤共振的原理,设计出一种新型传感器。它具有抗强电磁场的优点。经实验验证,达到了大型发电机在线检测的要求。     

A distributed temperature sensor based on liquid-core optical fibers

The principles of operation, the design, and performance of a fiber-optic temperature-distribution sensor are discussed. The sensor uses optical time-domain reflectometry (OTDR) to detect temperature-induced changes of backscatter power at many separate locations in the fiber. In liquid-core fibers, a sensitivity of2.3 times 10^{-2}dB/°C (0.54 percent° C^-1) was observed. A measurement accuracy of 1°C with a spatial resoltuion of 1 m is attainable over a fiber length of 100 m.     

基于OTDR的无源光网络在线监测系统研究

从无源光网络(PON)着手,首先简单介绍了PON的主要特点及其发展现状.在强调了PON网络全光在线监控系统的必要性及重要性后,着重描述了四种基于光时域反射仪(OTDR)的PON全光在线监测系统并分别概括了它们的特性,最后还列举了这四种监测系统的性能对比情况.     

A fuzzy-logic architecture for autonomous multisensor data fusion

Fuzzy logic techniques have become popular to address various processes for multisensor data fusion. Examples include the following: (1) fuzzy membership functions for data association; (2) evaluation of alternative hypotheses in multiple hypothesis trackers; (3) fuzzy-logic-based pattern recognition (e.g., for feature-based object identification); and (4) fuzzy inference schemes for sensor resource allocation. These approaches have been individually successful but are limited to only a single subprocess within a data fusion system. At The Pennsylvania State University, Applied Research Laboratory, a general-purpose fuzzy-logic architecture has been developed that provides for control of sensing resources, fusion of data for tracking, automatic object recognition, control of system resources and elements, and automated situation assessment. This general architecture has been applied to implement an autonomous vehicle capable of self-direction, obstacle avoidance, and mission completion. The fuzzy logic architecture provides interpretation and fusion of multisensor data (i.e., perception) as well as logic for process control (action). This paper provides an overview of the fuzzy-logic architecture and a discussion of its application to data fusion in the context of the Department of Defense (DoD) Joint Directors of Laboratories (JDL) Data Fusion Process Model. A new, robust, fuzzy calculus is introduced. An application example is provided     

Temperature sensor based on dielectric optical microresonator

An optical temperature sensor has been presented based on Whispering Gallery Mode (WGM) dielectric microresonator. The effect of Transverse Electric (TE) wave propagation in dielectric micro-spheres presented has been for optical resonances based on WGM. TE waves are characterized both theoretically and experimentally for large size parameter of the micro-spheres. A theoretical model has been developed based on asymptotic approach. The theoretical development is mathematically robust and significantly less complicated than existing approaches presented in the literature. The quality factor of experimental resonance spectra observed in the laboratory is calculated approximately in the order of 10⁴ which is sensitive enough to detect micro or nano level temperature changes in the surrounding medium. The sensitivity of the Morphology Dependent Resonance (MDR) temperature sensor is wavelength change of 10⁻⁹ m for one degree centigrade change in temperature. This sensor could potentially be used for nano technology, Micro-Electro-Mechanical Systems (MEMS) devices, and biomedical applications.     

一种EPON光缆在线监测系统

针对安徽省电力系统EPON网络的特点及电力系统现有光缆监测技术特点,提出一种"OTDR+光开关+合波器+光反射器(终端过滤器)"光缆在线监测系统设计方案。EPON光缆在线监测系统能够实时监测光缆线路的性能变化,及时发现故障隐患,迅速定位障碍点,有效减少故障的历时,从而降低因温度和应力等因素带来的电力系统光纤通信网的故障发生。     

基于LEACH路由协议的混合光无线传感网络研究

分析了基于低功耗自适应分簇(LEACH)路由协议的无线传感网络(WSN)在不同拓扑形状下的生命周期,并改进了长方形拓扑形状的路由协议。进而针对WSN在某些场合能量有限、易受干扰和安全性差等缺点,在长方形区域中引入分布式光纤传感结构。将传感光纤铺设在环境复杂和外界电磁波干扰大的监测区域,从而提高整个传感网络的生命周期和可靠性。理论分析和仿真结果表明,改进的拓扑和协议在提高可靠性的同时,有效地延长了光WSN的生存时间,性能优于传统LEACH协议。     

基于布里渊光时域反射的分布式光纤传感入侵定位检测系统

建立了基于布里渊时域反射(BOTDR)技术的分布式光纤传感入侵定位检测系统。采用自制的光纤单纵模分布反馈(DFB)激光器,利用边缘滤波(BPF)技术,简化了BOTDR系统中频率解调的方法,实现了对入侵应变事件的快速定位与检测。实验结果表明,当探测范围为10km时,系统的定位空间分辨率达到5m,应变分辨率达到200με,可以满足入侵定位实时检测的需求。     

Research on SFTS structure based optical fiber sensor

A single-mode-few-mode-thin-core-single-mode (SFTS) structure based optical fiber sensor is fabricated and experimentally studied. The sensing principle relies on the inter-modal interference. Since the core diameter of few-mode fiber (FMF) is larger than that of single-mode fiber (SMF), the FMF helps to allow more light to enter the cladding of thin-core fiber (TCF), which helps TCF to excite cladding modes. The interference between core and cladding modes in TCF occurs at the joint of lead-out SMF and TCF. Experimental results demonstrate a refractive index (RI) sensitivity of ?103.34 nm/RIU and a temperature sensitivity of 0.05 nm/°C. The proposed sensor not only can measure temperature, but also can measure RI. In addition, the proposed sensor is simple for without complicated fabrication process.     

A novel Cu(I) complex based organic ultraviolet optical sensor

A novel Cu(I) complex with the formula of [Cu(DPEphos)(Dicnq)]BF4(CuDD) was synthesized and characterized by X-ray single crystal diffraction method,in which DPEphos and Dicnq denote bis[2-(diphenylphosphino)phenyl]ether and 6,7-Dicyanodipyrido[2,2-d:2',3'-f] quinoxaline,respectively.Organic ultraviolet optical sensor based on photovoltaic diode is fabricated by using CuDD as an electron acceptor and 4,4′,4″-tris-(2-methylphenyl phenylamino) triphenylamine(m-MTDATA) as an electron donor.The sensor is sensit...     

A single-chip optical sensor with analog memory for motiondetection

A 64×64-pixel image sensor with full-frame analog memory and on-chip motion processor is presented. The processor consists of a charge amplifier and an analog subtractor. It uses the switched-capacitor technique and calculates the difference between the values of the signal on each pixel in successive frames. The rate can achieve up to 60 frames/s with limited area and power overhead. The analog memory required for the storage of the previous frame is implemented using implanted capacitors placed within the sensor array. Fabricated in a 1.2-μm standard CMOS process with an added metal 3 light-shielding layer, the circuit is fully functional and requires a total core area of 13 mm²     

一种新的气敏光纤传感材料

作者研制成功一种新的气敏光纤传感材料SnO2:ZnO,并对它作了甲醇试验。SnCl4:ZnCl2的重量比为1:1最好,是一种有前途的光纤(光学)气敏材料。     

高光反馈水平下光回馈传感器的模拟行为模型

基于Cadence公司的orcad10.5提出一种模拟行为模型来描述高光反馈水平下(适度光反馈水平和强光反馈水平)光回馈自混合干涉现象,该方法减化了光回馈自混合干涉现象中非线性方程的求解过程。不仅建立了高光反馈水平下光回馈传感器的模拟行为模型,搭建了软硬件结合的平台,同时也提供了一种对目标位移、速度、距离等进行测量的新的数据处理方法。     

弱光反馈水平下光回馈传感器的模拟行为模型

反射或散射光光强的变化及系统的非线性都将导致干涉模型的变化,从而造成干涉信号波形的变化。这些变化将增加测量过程中数据处理的复杂性。本文基于Cadence公司的orcad10.5提出一种模拟行为模型来描述弱光反馈水平下光回馈自混合干涉现象,该方法减化了光回馈自混合干涉现象中非线性方程的求解过程。不仅建立了弱光反馈水平下光回馈传感器的模拟行为模型,搭建了软硬件结合的平台,同时也提供了一种对目标位移、速度、距离等进行测量的新的数据处理方法。     

高光反馈水平下光回馈传感器的模拟行为模型

基于Cadence公司的orcad10.5提出一种模拟行为模型来描述高光反馈水平下（适度光反馈水平和强光反馈水平）光回馈自混合干涉现象,该方法减化了光回馈自混合干涉现象中非线性方程的求解过程。不仅建立了高光反馈水平下光回馈传感器的模拟行为模型,搭建了软硬件结合的平台,同时也提供了一种对目标位移、速度、距离等进行测量的新的数据处理方法。     

Integrated optical high-voltage sensor based on a polymeric Y-branch digital optical switch

An integrated optical high-voltage sensor is realized by fabricating a Y-branch digital optical switch in an electrooptic polymer. The measurement of ac high voltage is accomplished by using the linear transfer characteristics of the switch at zero bias voltage. Furthermore, the logarithmic ratio between the optical powers of two output ports may be used to remove the noise caused by the power fluctuations of a light source. The polymeric high-voltage sensor requires no electrical dc biases and no voltage dividers. It is also wavelength insensitive and fabrication-tolerant due to its use of mode evolution effects instead of interference. The measured sensing voltage range is as large as ac 500-V peak-to-peak.     

基于主动加热方法的隧道积水分布式光纤传感器

针对目前隧道积水事件及积水范围监测需求,研发了两种新型隧道积水传感器,提出了基于分布式温度传感(DTS)的隧道积水分布式感测方法。通过将传感光缆按二维平面螺旋封装方式提高了传感器的空间分辨率,利用主动加热方法,显著提高了水-气界面传感光缆的温度差异,进而实现对积水事件和积水范围的识别。通过室内模型试验,对传感光缆的性能及影响因素进行了研究。结果表明,研发的两种传感器均具有较高的空间分辨率,由于螺旋Ⅰ型的环间距更小,其空间分辨率及定位精度均高于螺旋Ⅱ型;在多种典型工况下两种传感器均可以准确识别积水的水-气界面,定位误差均小于10 cm;适当增大加热温度可以提高传感器的定位精度,50℃加热工况时的定位精度明显优于35℃和20℃。     

基于弯曲损耗的光纤温度传感器

为了推导多模光纤弯曲损耗与弯曲半径、环境温度的关系,采用了WKB法求解非均匀直光纤的传播模数,并将弯曲光纤的有效折射率、弯曲光纤截止传播常数和光纤的热光效应同时引入到非均匀直光纤有效传播模数中。利用多模光纤进行实验验证,研制出测温灵敏度为0.1/℃、测温范围为10℃～70℃的光纤温度传感器。结果表明,弯曲损耗随弯曲半径的增大而减小,随环境温度的升高而减小,可以利用弯曲损耗测量环境温度。     

基于F-P的光纤气体检测系统

简单介绍了利用F-P的可调谐性提出的一种新型的基于1550nm宽带光源的光纤气体检测系统的工作原理、实验装置软硬件设计以及利用该实验装置进行实验数据处理的思想--FFT一次谐波算法和计算光谱面积的算法.利用一次谐波的方法进行了实验,得出实验结果和结论.     

Integrated optical SPR sensor based on mode conversion efficiency

A novel type of integrated optical surface plasmon resonance (SPR) sensor is proposed, for which the operational principle is based on the launching efficiency of eigenmodes in the sensor head. The sensor comprises an inverted-rib-type dielectric waveguide, a portion of which is covered with a thin gold layer. Eigenmodes in the sensor head are coupled modes of a surface plasmon polariton and a dielectric guided wave. The excitation efficiency of the coupled modes varies significantly depending on the refractive index of the analyte medium on the sensor head. Following this principle, the transmission coefficient of light through the sensor head can be used as a sensitive measure of the variation in the refractive index of the analyte medium.