Propagation model and error analysis of an E-field sensor based on pockels effect and waveguide

Electric field measurement sensors based on the crystal Pockels effect are widely used. Currently, the development aims for electric field sensors are mainly focused on miniaturizing and integrating the sensor structure and improving measurement sensitivity and precision. The goal of this study was to analyse the sources of error in Pockels effect electric field measurement sensors, consider the mutual influence and accumulation effect of the various error factors, and establish a basic mathematical model of the measurement system with error components. Calculation and analysis were used to classify the function and change trend of several main errors, providing reference data for the structure design and error compensation of the sensor. The results show that the polarizing angle and the analyser angle have the same influence on assembly error. The inherent error is positively related to the electric field intensity. The periodic accumulation characteristic error under large electric field is also discussed. In order to avoid this error under an intense electric field, a suitable test electric field range was determined.     

A New Forward-Problem Solver Based on a Capacitor-Mesh Model for Electrical Capacitance Tomography

An electrical-capacitance-tomography sensor consists of a set of measurement electrodes. It is difficult to calculate the capacitance for a given sensor structure and given permittivity distribution, which is called solving the forward problem, theoretically. Therefore, finite-element methods (FEM) and finite-difference methods are commonly used to solve the forward problem and to generate a sensitivity matrix for image reconstruction. This paper presents a new approach to solving the forward problem based on a capacitor-mesh model. It has been used for iterative image reconstruction using an updated sensitivity matrix according to an estimated image. In this paper, some simulation results are presented and compared with the results obtained using an FEM software package from Ansoft Company, showing that the new approach is promising.     

一种基于光纤F-P腔的石墨烯谐振式压力传感器

谐振式传感器具有良好的重复性、分辨率和稳定性,全光纤谐振式微型传感器则集合了微纳结构与光纤传感特性两者的优点。石墨烯作为近年来发现的一种新型材料,具有良好的热学和力学特性,可以作为谐振式传感器中的敏感元件。本文提出了一种基于光纤F-P结构的石墨烯谐振式压力传感器,其兼具微机械传感器和光纤谐振器的优点,具有较高的谐振频率,在测量压力的实验中展现出良好的性能,压力灵敏度最高可达2. 93Hz/Pa,具有重要的应用价值。     

All-Dielectric Electrooptic Sensor Based on a Polymer Microresonator Coupled Side-Polished Optical Fiber

A novel electrooptic (EO) electric field (E-field) sensor based on side-polished fiber coupled with an EO polymer microring resonator is proposed and demonstrated. An EO polymer waveguide with a ring shape is fabricated on the polished flat of an optical fiber. Light in the fiber evanescently couples into the resonator and forms resonant modes for certain wavelengths and produces notches in the output intensity of the fiber. External electric fields change the index of refraction of the ring waveguide and therefore dither its resonant wavelengths. For light of wavelength on the slope of a resonance notch, a change in the output intensity can be detected. The sensor is all dielectric without metal layers to distort the measured E-field. The resonant structure allows the sensor to potentially have much higher sensitivity than other electrooptic sensors based on Mach-Zehnder or polarization modulation. Since electrooptic polymers have higher electrooptic coefficients, lower dielectric constants and faster electrooptic responses than inorganic crystals, higher sensitivity, lower invasiveness, and higher bandwidth of E-field sensing can be expected. This sensor eliminates unreliable fiber-to-waveguide butt coupling as well as the high propagation loss encountered in the long straight EO polymer waveguides of sensors based on Mach-Zehnder structures. By using the fiber itself as the supporting substrate of the ring waveguide, the sensor can have small size and low disturbance to the measured electric field. The concept is demonstrated using AJLS103 EO polymer. A sensitivity of 100 mV/m has been achieved at frequencies up to 550 MHz (limited by the measurement system)     

基于里德堡原子的电场传感技术

概述了基于里德堡原子的电场传感技术的基本原理,分析了里德堡原子电场测量具有的高灵敏度、宽频、可溯源至国际单位制（International System of Units, SI）、高空间分辨力等优势。讨论了激光参数、探测器噪声、环境电磁场干扰等因素对里德堡原子场强测量灵敏度与测量频率响应带宽的影响,介绍了频率调制、重泵浦、参数优化等提高场强测量灵敏度的方式,并阐述了单辅助场原子外差法、双辅助五能级外差法等提升测量频率响应带宽的方法。探讨了里德堡原子电场传感技术在计量、通信、雷达、成像等方面的应用情况,指出应通过优化原子气室结构、设计高性能光电探测器、提升光学腔性能等方式进一步提高里德堡原子电场测量灵敏度;应深入研究里德堡原子电场测量的不确定度来源,并对里德堡原子传感器进行全面的测试和表征;应开展里德堡原子电场测量相关装置的小型化、工程化设计研究,从而进一步提升里德堡原子电场测量技术的实际应用性能。     

Multicomponent lifetime-based pH sensors utilizing constant-lifetime probes

A multicomponent luminescent sensor system is described that uses probe species with constant lifetimes to generate an analyte-dependent change in the apparent sensor lifetime. This new sensing scheme not only allows for lifetime-based measurement techniques to be applied to sensors that employ static quenching interactions but also provides the ability to vary the sensitivity of the sensor system with simple changes in instrumental parameters. A model for the multicomponent sensor is presented, followed by data measured using a prototype pH sensor based on the model.     

现代湿度测量方法评述

介绍了现代湿度测量中几种较为常用的测量方法,其中包括露点法、电湿度传感器和吸收光谱法等,并从工作原理、仪器构造等方面进行了详细的论述.     

High Pressure Sensor Based on Fiber Bragg Grating and Carbon Fiber Laminated Composite

A simple anisotropic structure made by carbon fiber laminated composite for fabricating a high pressure sensor is reported. A pressure sensor with good sensitivity over a broad measurement range is fabricated by using fiber Bragg grating and the anisotropic carbon fiber laminated composite structure. The characteristic responses of pressure and temperature of the new pressure sensor are analyzed. Experimental data show that when the pressure changes from 0 to 70 MPa, the wavelength shift of the fiber Bragg grating pressure sensor is up to 7 nm, corresponding to a sensitivity of 10 kPa/pm.      

HCPCF端面塌陷成腔工艺的F-P应变传感器

本文提出了一种新型测量应变的空芯光子晶体光纤(HCPCF)法布里-珀罗(F-P)干涉传感器,HCPCF的一端与单模光纤熔接形成反射面1,另一端在熔接机内通过电极放电使端面完全塌陷形成反射面2,构成以HCPCF为腔体的新型F-P干涉传感器。实验结果表明,腔长2mm的传感器在室温下的应变灵敏度为3.1nm/με,线性度为0.9992,极限腔长改变量为3827.3nm。温度在0～150℃的温度变化范围内,腔长的改变量约为0.17μm。理论和实验结果表明该新型传感器具有制作工艺简单、应变灵敏度高、温度灵敏度低和没有迟滞现象等优点。     

一种流通过程现场测试跌落方位传感器的研究

跌落方位是跌落冲击中的一个重要参数,测量较为困难,提出了一种基于电容传感器的跌落方位现场测试新方案,分析了其基本结构、测量电路、测试原理和方法.     

一种新型智能真空测量仪的研制

本文叙述的是以 DL- 5电离真空规为传感器 ,用单片机作控制和测量的一种新型智能真空测量仪。文中简述其工作原理 ,详叙实现它的方法。该仪与别的智能真空测量仪不同的方法是 ,采用单片机控制发射电流 ,这样不仅提高了测量精度 ,而且将发射电流参入计算 ,扩展了量程范围。该仪采用了软件抗干扰措施 ,有自诊和自保护功能     

基于双模LPFG折射率不敏感双参量传感器

环境折射率和环境温度变化是影响光纤应变测量误差的主要因素.本文利用双模光纤纤芯双模式(LP01和LP11)支持特性设计了一款环境折射率不敏感的双模光纤(DMF)长周期光纤光栅LPFG)应变传感器.设计了传感器模型结构,制作了最优化参数的传感器样品.实验测试了DMF-LPFG传感结构对外部环境中应变、温度和折射率的响应....     

A Novel Fiber-Optic Tapered Long-Period Grating Sensor for Pressure Monitoring

The method and the required installations for fabricating tapered long-period fiber gratings can be simpler than that of standard fiber Bragg gratings, and the fabrication process is faster. To our knowledge, the tapered long-period fiber grating pressure sensor is presented here for the first time. In this paper, the fabrication method for tapered long-period fiber gratings, the sensing principle, the sensor structure, the measurement setup, and the preliminary results are presented and discussed. The pressure sensitivity of the sensor is as high as 5.1 pm/bar.     

Liquid crystal infiltrated photonic crystal fibers for electric field intensity measurements

The application of nematic liquid crystal infiltrated photonic crystal fiber as a sensor for electric field intensity measurement is demonstrated. The device is based on an intrinsic sensing mechanism for electric fields. The sensor probe, which consists of a 1 cm infiltrated section of photonic crystal fiber with a lateral size of ～125 μm, is very compact with small size and weight. A simple all-fiber design for the sensor is employed in an intensity based measurement scheme. The transmitted and reflected power of the infiltrated photonic crystal fiber is shown to have a linear response with the applied electric field. The sensor is operated in the telecommunication window at 1550 nm. The temperature dependence of the device at this operating wavelength is also experimentally studied and discussed. These structures can be used to accurately measure electric field intensity and can be used for the fabrication of all-fiber sensors for high electric field environments as both an in-line and reflective type point sensor.     

基于集成氮化硅微腔的光学传感芯片研究

近年来随着传感器在生物探测领域的应用,提高传感器芯片的灵敏度成为研究的热点。利用氮化硅微腔灵敏度高、成本低、易于集成的优点,设计制造了1550 nm波长下二维、三维结构品质因子分别为1.6×104和4×103的悬空耦合传感器芯片,并详细研究了集成氮化硅微腔光学传感芯片在折射率测量方面的应用。     

Wave-front sensing by pseudo-phase-conjugate interferometry

A wave-front sensor based on pseudo-phase-conjugate interferometry is presented. We show that a pseudo-phase-conjugate interferometer is suitable for the measurement of phase distribution on a propagating wave. This new method may be employed for optical workshop applications and wave-front sensing for adaptive optics. The theoretical sensitivity of the interferometer is twice that of the Hartmann-Shack wave-front sensor. Preliminary laboratory experiments demonstrate excellent performance and consistency with computer simulations.     

Design and analysis of an integrated antiresonant reflecting optical waveguide refractive-index sensor

An integrated optical waveguide refractometer, believed to be novel, is presented. The sensor is based on an antiresonant reflecting optical waveguide and uses the strong attenuation dependence on the refractive index of antiresonant cladding layers as the sensing principle. The theory and the operation of the sensor are discussed in terms of one- and two-dimensional geometry. The theoretical predictions and numerical analysis show that a versatile sensor can be realized. The design trade-offs are discussed, and the sensitivity and measurement range are presented.     

超高温传感器用感温材料与结构特性分析

针对现有蓝宝石光纤温度传感器测温上限难以突破1 700℃的瓶颈问题,本文分别从传感器测温结构和感温材料两方面进行了分析改进,以满足对2 000~2 500℃超高温的测量需求.提出了一种接触-非接触相结合的新型传感器测温结构,并结合非接触式测温结构特点给出了Plank黑体辐射温度误差补偿公式,解决了非接触结构的准确测温问题.结合不同感温材料特性分别对难熔金属、陶瓷基复合材料和C/C复合材料的高温性能进行分析比较,包括材料强度、密度、抗氧化性、塑性、熔点等,筛选出适合作为超高温传感器的备选感温材料.针对筛选出的感温材料设计了抗热震性试验和抗氧化烧蚀试验,实验结果表明Hf B2-Si C复合材料能够满足超高温环境下对感温材料物理特性的特殊需求.传感器温度试验结果表明,采用接触-非接触式新结构和Hf B2-Si C感温材料的新型光纤温度传感器可对2 500℃高温进行长时间稳定测量,测量精度达到±1%.     

静电传感器空间灵敏度特性研究

对应用于气-固两相流参数检测的静电传感器的空间灵敏度分布特性进行了研究。建立了静电传感器的数学模型,并应用大型有限元分析软件ANSYS对不同的传感器结构尺寸内的静电场分布进行了数值分析,进而获得了静电传感器空间灵敏场分布。结果表明：静电传感器的灵敏场分布不均匀,在不同的轴向和径向位置灵敏度不同,壁面附近灵敏度较高,轴线处较低;轴向长度越长,灵敏度越高,灵敏场相对越均匀;由于边缘效应,静电传感器的灵敏空间略大于其几何结构所确定的空间。