反射式光纤位移法检测轧辊磨损度中实用电路的设计

利用反射式光纤位移传感器的工作原理，通过对反射光强信号的检测，提出了一种用于轧辊磨损度在线非接触检测的光电检测法，并重点设计了用于反射式光纤位移法检测轧辊磨损度系统的实用电路。根据轧辊磨损度测量过程的特点及精度要求，阐述和分析了传感器电路系统的原理、组成及性能。理论和实验研究表明，该电路系统工作稳定，精确度和灵敏度均可满足实际要求。此电路系统稍加改进还可适用于类似条件下用反射式光纤位移法进行测量的其他系统。     

Simplified Formula of Bending Loss for Optical Fiber Sensors

A simple fiber-optic bending loss formula is achieved for optical fiber sensors. This simple formula considers various bending radii, number of turns, extra bending angle, and wavelength and has good agreement with theoretical and experimental data. We also propose a simplified formula for sensitivity of the fiber-optic bending loss in this article. The defined sensitivity formula has the benefit of showing parameters for fiber-optic bending sensor systems.     

Simplified Formula of Bending Loss for Optical Fiber Sensors

A simple fiber-optic bending loss formula is achieved for optical fiber sensors. This simple formula considers various bending radii, number of turns, extra bending angle, and wavelength and has good agreement with theoretical and experimental data. We also propose a simplified formula for sensitivity of the fiber-optic bending loss in this article. The defined sensitivity formula has the benefit of showing parameters for fiber-optic bending sensor systems.     

Diode-lasers based apparatus and method for single-mode fibers spectral splice loss measurements

Arc-discharge fusion splicing is widely used in the telecommunication industry for joining single-mode optical fibers to Er-doped fiber coils. These coils are used as the gain medium in erbium-doped amplifiers (EDFAs). The quality and integrity of splicing these coils to fibers can impact key EDFA performance parameters. This article describes an automated splice loss and Er-doped fiber absorption measurement system. The measurement system is equipped with 1310, 1550 and 1563 nm DFB lasers, broadband light source, InGaAs detectors and fiber-optic internal standards. Furthermore, the article describes a method for measuring splice loss between Er-doped fiber and the fibers spliced to coil ends. The system controls splice loss between SM-28 or HI980 fiber and Er-doped fiber to 0.094 ± 0.052 dB at 1550 nm. Moreover, the system can measure accurately Er-doped fiber absorption to within ±3.19% at 1563 nm.     

基于薄芯光纤模态干涉技术的曲率光纤传感器

提出了一种新的基于薄芯光纤模态干涉技术的光纤曲率传感器。在单模光纤的中间部分插入薄芯光纤用于传感光路,没有插入薄芯光纤的单模光纤用于参考光路,以消除环境对曲率测量的影响。由于插入的薄芯光纤和单模光纤纤芯失配,导致包层的高次模被激发,并与纤芯模在单模光纤内形成干涉。当改变薄芯光纤的曲率时,沿纤芯和包层传播的模态和光纤长度会发生改变,使得干涉谷峰发生平移。将传感光纤的两端固定的平移台上,当调节平移台距离时,薄芯光纤的曲率发生改变,导致干涉谷峰向短波方向平移。通过观察谷峰的平移距离可以实现曲率的传感测量。实验表明,该装置具有低损耗、低成本和高灵敏度的特点。     

Fiber-optic reflex sensor for in-line production measurement

The paper describes experiments concerning distance measurement with fiber-optic sensor and improvement of the measurement principle. The sensor probe was well-designed with a small structure and multi-function. The novel optical fiber probe arrangement as well as the possibilities of use for complex measurement problems are explained using the measurement of an internal screw thread as an example. The experimental results show that the measurement uncertainty of the thread minor diameter can reach ±10 μm, and the stability of the measurement system is better than 0.07%.     

Characteristics analysis of photonic crystal fiber with rhombus air-core

Aiming at the requirement of low confinement loss and multiple zero dispersion points in fiber-optic sensing systems and optical communication networks, a new type of photonic crystal fiber (PCF) with rhombus air-core is proposed. By using finite element method (FEM), the structural and optical properties of the proposed PCF are analyzed. Simulation results reveal that the proposed PCF has lower confinement loss with 10^?3 dB/m and higher birefringence. Besides, two zero dispersion points can be obtained after optimization. The proposed PCF may have important applications in fiber-optic sensing systems and other aspects.     

Electric current measurement using fiber-optic curvature sensor

A novel fiber-optic curvature sensor, which can measure curvature directly, has been developed in recent years. The electric current measurements system based on fiber-optic curvature sensor and electromagnetic principle is developed. A fiber-optic curvature sensor is bonded to a thin-walled cantilever and two circular magnet targets with the same parameters are configured at the tip of the cantilever symmetrically. In this case, the throughput of the sensor will be changed due to the bending deformation of cantilever, which is proportional to the electromagnetic force caused by measured electric current. Direct and alternate characteristics of the proposed measurement system are studied experimentally. The results show that the measurement errors are within the range of ±5.5 mA and the corresponding accuracy is within 1% at the current measurement range from −300 mA to 300 mA, which indicate the feasibility of the proposed measurement system.     

Light intensity modulation fiber-optic sensor for curvature measurement

A light intensity modulation fiber-optic sensor, which can measure curvature directly, has been developed. It is suitable for the measurement of thin, embedded or highly flexible structures. An experimental analysis on the static and dynamic characteristics of sensor has been undertaken. The results show that the output voltage has polarity and a good linear relationship with curvature when the curvature radius is larger than 60 mm. The mathematical model relating the relative output loss, parameters of sensitive zone’s configuration (depth, number, height and half angle of tooth) and bending radius is described analytically based on the geometric optics. Curvature fiber-optic sensors can be used to build a quasi-distributed fiber-optic sensor system, which can measure curvature and torsion angle simultaneously.     

海水盐度光纤遥测技术研究——测量原理

提出了一种用于海水盐度检测的光学新方法 ,利用光纤光学技术与CCD检测相结合的测量技术 ,并通过测量待测海水与参考蒸馏水的折射率差的方法 ,减小了盐度测量受温度的影响 ,并可实现海水盐度的自动化远距离遥测。建立了测量原理的理论模型。该系统水下的测量探头部分由无源的全光学结构组成 ,具有结构紧凑、精度高、抗电磁干扰、防燃、防爆、可柔性弯曲等诸多优点 ,在海洋勘探 ,环境监测以及军事、进出口贸易中的水尺计重等领域有广泛的应用前景和实用价值     

评估环圈光纤机械可靠性的模型

为评估应用于光纤陀螺和光纤电流传感器等传感领域的光纤环圈的机械可靠性,排除光纤涂覆和环圈灌胶等因素,必须评估所用光纤在弯曲状态下的机械可靠性.在已被广泛接受的均匀拉伸应力状态下通信光纤的机械可靠性模型基础上,根据这种环圈光纤在弯曲状态下的一般应力分布,对于绕环张力和弯曲应力同时存在的情形,建立了评估这种环圈光纤的机械可靠性的一种模型.该模型通过采用弯曲状态下光纤表面的最大弯曲应力值,和由于一般情况下弯曲中轴内侧的压缩应力远小于外侧拉伸应力的这一事实而忽略内侧的压缩应力,从而简化了弯曲应力的不均匀分布;同时通过该模型中所含的多个参量的选择给出了最为保守的结果.利用该模型进行的数值计算预测了采用不同直径的光纤分别绕制的不同环圈直径的环圈光纤在不同服役条件下的机械可靠性.结果表明,除了光纤半径和疲劳因子等这些光纤自身的固有因素外,绕环张力、环圈半径和筛选张力等工艺参量对环圈光纤的机械可靠性也是有重要影响.     

基于稀土掺杂光纤的强度调制型弯曲传感器

研究了一种基于稀土掺杂材料的新型周期性微拉锥玻璃光纤及其弯曲传感应用技术. 该光纤的纤芯和包层分别由两种硅酸铅玻璃材料组成,具有可塑性好和易于形成微拉锥的特点. 该传感器的核心敏感体由聚焦的CO₂激光束对稀土掺杂光纤进行周期性和等间距加热方式制备. 论文以该敏感体为核心,结合精密位置移动平台和光学测量平台,构建了基于强度调制的弯曲传感测量系统. 理论研究和实验结果表明,这种弯曲传感测量系统的传输光强灵敏度达到-28.2 μW/m,测量误差低于±1%,具备实际的工程应用价值. 关键词： 稀土掺杂光纤 微拉锥 弯曲传感 强度调制     

Feasibility study on fiber-optic goniometer for measuring knee joint angle

In this study, we fabricated a fiber-optic goniometer using a plastic optical fiber, a light-emitting diode, and a photodiode. The cladding of the plastic optical fiber was removed at 0.5–3mm intervals regularly to increase the bending loss of the plastic optical fiber. Also, the output voltages of the photodiode based on light intensity that measured using the fiber-optic goniometer were measured light intensities using the fiber-optic goniometer were measured to evaluate the linearity of the fiber-optic goniometer. Finally, we measured the responses of the fiber-optic goniometer for gait speeds of 3, 5, and 10 km/h using a data acquisition board and a LabVIEW program.     

光纤超声传感器及应用研究进展

光纤超声传感器通过检测光纤内传输光的强度、波长、相位、偏振态等参数感知超声波的相关信息.相比于传统的电类超声换能器,光纤超声传感器能够实现宽频带超声波信号的高灵敏探测,且其良好的抗干扰能力和复用性,可有效地提高超声波探测的可靠性和效率,在水下国防安全、生物成像、无损探伤、地震物理模型成像等领域具有巨大的应用潜力.目前,按照传感结构,光纤超声传感器可分为光纤强度调制型、光纤干涉型和光纤光栅型,并在不同方面发挥着各自的优势,均受到关注.本文主要综述了这几种传感器的传感机理、实现方法、发展现状,总结了光纤超声传感器的几个应用领域及面临的科学技术挑战,重点讨论了光纤超声传感器作为一种新技术应用于地震物理模型成像.     

Simultaneous measurement of axial strain, temperature, and transverse load by a superstructure fiber grating

A novel and simple fiber-optic sensor based on a superstructure fiber grating for simultaneous measurement of temperature, axial strain, and transverse load is proposed and demonstrated. By measurement of the shift and split of broadband and narrow-band loss peaks, one can determine the temperature, axial strain, and transverse load simultaneously over the ranges 0-140 degrees , 0-1200muepsilon, and 0-0.3 kg/mm, respectively.     

光纤复合型油气井下压力温度测量系统

针对目前广泛使用的电子式油气井下压力温度测量系统可靠性低、高温环境漂移大的不足,设计了一种基于非本征型F-P干涉仪(EFPI)和光纤布喇格光栅(FBG)的复合型油气井下压力、温度测量系统,详细说明了其工作原理、传感器组成和信号解调方法,初步试验结果表明,该测量系统不仅克服了电子测量方式的不足,而且具有复用性好、测量精度高等优点.     

In-line fiber-optic etalon formed by hollow-core photonic crystal fiber

A novel fiber-optic in-line etalon formed by splicing a section of hollow-core photonic crystal fiber (HCPCF) in between two single-mode fibers is proposed and demonstrated, for the first time to our knowledge. Such a HCPCF-based etalon acts as an excellent optical waveguide to form a Fabry-Perot interferometer and hence allows the cavity length to be as long as several centimeters with good visibility as the transmission loss of the HCPCF is much smaller than that of a hollow core fiber; this offers great potential to generate a practical dense fiber-optic sensor network with spatial frequency division-multiplexing. This novel etalon is demonstrated for strain measurement, and the experimental results show that a good visibility of 0.3 and a strain accuracy of better than +/- 5 microepsilon are achieved.     

光缆弯曲对激光能量传输效率的影响

研究了激光火工品系统中光缆弯曲对激光能量传输效率的影响.对7种不同规格光缆在弯曲半径R为2.5~175 mm范围内的弯曲传输特性进行了试验研究.结果表明,R/2a＜50 时,透光量已开始下降;R/2a≈20 时,激光能量传输效率明显下降.根据实验结果,通过数据拟合处理得出了7种规格光缆弯曲损耗的半经验公式,该公式可以直接用于激光火工品系统光缆的传输设计.     

Fiber-optic systems for temperature and vibration measurements in industrial applications

Fiber-optic systems for temperature and vibration measurements have been developed. It is shown that using the principle of wavelength conversion in the sensor, measurement systems, in which only one fiber is used for the connection of the sensor to the instrument, can be realized. The measuring accuracy is practically independent of the properties of the fiber-optic system such as fiber length, fiber diameter and type of connectors used. These properties are very important, reducing installation problems and costs. The adoption of semiconductor technology allows batch fabrication of sensor elements. For the prototype temperature instrument an accuracy of 0·5°C was obtained in the temperature range 0 to +200°C. Fiber-optic accelerometers for vibration measurements with a resolution of 0·05 g and a dynamic range of 70 dB have been realized. The systems have been tested in different industrial environments and have properties that make them suitable for many industrial applications. Advantages of fiber-optic systems are their noise immunity, galvanic isolation and inherent intrinsic safety.     

光纤双向应变-位移点式传感器

选择不同间距的基片自由端和不同长度的自由悬垂光纤研制了利用光纤弯曲损耗的光纤双向应变-位移传感器.该传感器可分别用于测量应变和位移.实验表明:悬臂梁上的应变标准误差约为～26 με.微位移架上的位移标准误差约～0.06 mm.基本满足建筑结构对测量精度的要求.