具有温度自补偿功能的宽频带光纤电场传感器

光纤电场传感器抗电磁干扰能力强、响应速度快，在电力设备运行状态和绝缘状况的监测领域有着广阔的应用前景。现有的光纤电场传感器由多个不同功能的分立光学器件组合而成，光路耦合对准困难、光功率损耗大、灵敏度低。此外，温度交叉敏感问题进一步限制了传感器的实际工程应用。为克服现有技术难题，提出一种以特种功能光纤取代分立光学器件，进而形成全光纤电场传感器的技术思路。传感器中的起偏器、检偏器、波片等功能器件均在光纤上实现，避免了分立元件之间对准、耦合等带来的传感器结构不稳定、性能低等问题。此外，通过双晶体正交级联光路结构的设计，赋予传感器温度自补偿功能，实现对温度交叉敏感的有效抑制。实验结果表明，传感器可同时对50 Hz低频电场和纳秒级脉冲电场进行有效捕获，环境温度变化给测量结果带来的误差仅为0.1%/℃。全光纤电场传感器结构简单、稳定性好、测量频带宽，在电力设备快速暂态过电压的测量方面有着重要的潜在应用价值。     

变压器局部放电光纤超声检测技术及新复用方法

传统的变压器局部放电声波检测技术主要是使用压电陶瓷传感器进行外置式检测,检测效果较差。光纤超声传感器具有绝缘性能好、抗电磁干扰性能优异、尺寸小等优势,可深入变压器内部感知微弱超声信号,这为变压器局部放电检测提供一种全新的解决方案。目前,国内外诸多研究机构已针对于变压器局部放电检测需求研制出各种光纤超声传感器。这些传感器在实验室研究中表现出优异的检测性能,但尚鲜有工程应用。此外,文献报道的光纤超声传感器主要为单点式结构。光纤超声传感器的多路复用问题一直未能得到很好的解决。为此,对现有光纤超声传感器的研究现状进行总结,从基本原理、结构参数、性能指标等方面进行对比分析,为推动光纤超声传感器应用于现场电力变压器局部放电检测提供理论参考。并针对于光纤超声传感器多路复用问题,提出一种基于光频域扫描干涉仪的分布式光纤超声传感系统,该系统能够对变压器局部放电产生的超声波进行多点同步检测,实现放电源定位。     

光纤F-P局部放电检测传感器优化设计

本文中作者根据高斯光束耦合理论、多光束干涉理论、弹性力学原理和有限元MEMS分析,对现有光纤型F-P传感器的结构进行了优化设计。     

光纤点式液位传感技术的研究现状

光纤液位传感器由于其具有电气隔离、抗电磁干扰、耐腐蚀等特性,适合在易燃易爆的环境下安全工作。光纤传感器一般都是根据光导纤维中的光信号在不同介质中传输特性不同,来对液位进行测量。光纤液位传感器包含连续液位传感器与点式液位传感器,点式液位传感器用于对特定液位点进行指示和报警。本文介绍了基于光的受抑全内反射、菲涅尔反射、光的散射、光纤的弯曲损耗4种原理的光纤点式液位传感器,并分析了每种传感器的结构与工作原理、精度等重要性能及优缺点,最后描述了其发展现状与趋势。     

换流变压器有载分接开关磁热耦合仿真计算与应用

本文中笔者对分接开关整体结构进行合理简化,建立了有载分接开关磁-热耦合的有限计算模型.对换流变有载分接开关磁热耦合仿真进行了计算分析,分析了漏磁集中分布特性、欧姆损耗与漏磁损耗对温升的影响特性.     

液-固复合介质对光纤法-珀局部放电超声响应强度影响分析

非本征光纤法-珀(F-P)传感器置于电力设备内液体绝缘检测局放声信号面临灵敏度低的问题。由于不同介质结构的声压分布影响灵敏度,采用声场有限元方法分析声波机械能在液-固复合介质中的暂态传递过程,对比超声波经液-固-液介质与单一液体介质传播后的声压大小,并分析固体物性参数对声压的影响,提出利用复合介质结构增强声压提高局放检测灵敏度的方法。分别采用PZT和板-板电极为连续超声源和局放声波源,对比F-P传感器在液体介质和液-固-液介质中的响应幅值。结果表明,液-固-液声耦合结构对声压有增强作用,且增强大小与传感器和固体介质的距离、固体介质物性参数相关;F-P传感器在液-固-液耦合结构中的局放响应幅值约是纯液体中的2倍。     

直线型、螺线管嵌套型及多光路反射式光纤电流传感器结构设计与仿真

小信号测量领域特别是局部放电检测中,全光纤电流传感器在灵敏度方面存在较大问题,针对该问题进行了研究。首先给出了光纤模型中Faraday旋光效应的经典理论解释,并对折射率表达式进行了修正,在此基础上设计了传统直线型、螺线管嵌套型和多光路反射式等3种光纤电流传感器结构。然后使用COMSOL多模场耦合仿真软件对所设计的3种光纤传感系统的传输场进行了计算仿真和对比分析,结果表明螺线管嵌套型全光纤电流传感器和多光路反射式光纤电流传感器的灵敏度分别比传统直线型光纤电流传感器高1 000倍和600倍以上。最后对所设计的2种新型传感器性能关系进行了分析,结果表明螺线管嵌套型光纤电流传感器加工精度要求不高,传感光纤的安装位置对测试结果影响不大;多光路反射式光纤电流传感器加工精度要求很高,传感头的安装位置对测试结果影响不大。综上所述2种新型传感器均使灵敏度得到极大改善,且在实验测试中即使传感头位置变化对测试结果也影响不大。未来将依据所设计的系统对传感器的潜在应用进行进一步的实验研究。     

对日本LC-1003-10型光纤活动连接器的分析

关于光纤活动连接器,目前不少单位正在研究各种性能稳定、工作可靠、加工方便的结构形式,以使其更加实用化。分析国内已定型的光纤活动连接器的几种结构,影响其性能指标——主要是指要求插入损耗低的原因是以插针外圆为基准的光纤对中心问题,以及光纤端面抛光质量问题。如果在结构上及加工上分别解决这两个问题,就可以在保证性能指标的前提下,走出实验室在野外操作。也就可以直接将活动连接器做在光缆上,从而减少一个固定接头的损耗。现有连接器的光纤对中心工作,大都在显微镜下进行,同时需用专用的调中心夹具,采用三圆调中心法,将光纤事先固定在内针管中,然后再调整使其在外针管外圆的中心,第二次加以环氧固定。光纤端面     

对射式螺旋形光纤液位传感器的设计与实现

介绍了一种将对射和螺旋两种结构结合在一起的光纤液位传感器。该传感器以两根侧发光光纤为基础,其中一根作为发射光纤,另一根作为接收光纤,当液面变化引起外部介质折射率发生变化时,发射光纤中光功率的损耗量会发生变化,耦合进入接收光纤的光功率会随之变化,通过检测此变化量即可获知液面高度信息。相对于直接使用两根直侧发光光纤对射的结构而言,螺旋结构的引入会提高光功率相对变化量,从而使其获得更好的性能。实验结果表明,该传感器能够实现液位的连续测量,并具有较好的重复性能。     

一种微带线到带状线宽带垂直耦合过渡结构

针对基于微波多层介质板的微带线到带状线过渡问题,提出了一种微带线到带状线宽带垂直耦合过渡结构,通过地层的圆形开孔完成微带线与带状线椭圆形贴片间的电磁耦合与匹配设计,实现了微波信号在微波多层介质板内跨层传输。将微带线到带状线宽带垂直耦合过渡结构在三维电磁场仿真软件中进行了建模,并对背对背结构进行了仿真、加工与测试。测试结果表明,在7~13 GHz的频带范围内输入输出回波损耗小于-12 dB,插入损耗最小为1.48 dB。该微带线到带状线宽带垂直耦合过渡结构具备了良好的性能,同时具有电路结构简单、加工方便等特点,在微波电路设计方面具有较高的实用价值。     

微型偏光器的偏振测量技术

本文描述了微型偏光器偏振特性的测量装置及测量方法。利用该装置对微型偏光器进行了测量，得到了消光比、插入损耗、衰减系数等参量的测量值。测量中使用了光纤位移传感器，对衰减与位移的关系进行了动态测量。     

Electrostatic MEMS variable optical attenuator with rotating folded micromirror

The design and fabrication of an electrostatic MEMS variable optical attenuator (VOA) is described. The VOA is a reflection type with a folded micromirror actuated by a comb-drive actuator. The VOA is fabricated by a simple single-mask process. One photolithography and subsequent deep silicon reactive ion etching define all the microstructures of the VOA. The folded micromirror structure can reduce the overall size of the device by enabling the parallel alignment of an input fiber and an output fiber. Lensed fibers are used to maximize the coupling efficiency and the ease of assembly. The electrooptic characteristics and dynamic characteristics of fabricated VOA are measured. The initial insertion loss is 0.5 dB at 1550 nm and the maximum attenuation is 45 dB, respectively. The polarization dependent loss is measured to be 0.2 dB at 20-dB attenuation. The response time for maximum attenuation is less than 5 ms.     

A silicon MEMS optical switch attenuator and its use in lightwavesubsystems

A single-mode fiber connectorized microelectromechanical systems (MEMS) reflective optical switch attenuator operating in the 1550-nm wavelength region is described. The device consists of an electrostatically actuated gold-coated silicon vane interposed in a fiber gap yielding 0.81-dB minimum insertion loss in the transmit state and high transmission isolation in the reflection state with 2.15-dB minimum return loss. The switch attenuators also work as continuously variable optical attenuators capable of greater than 50-dB dynamic range and can be accurately regulated with a simple feedback control circuit. Switching voltages were in the range of 5-40 V and a switching time of 64 μs was achieved. The MEMS switch can be used in optical subsystems within a wavelength-division-multiplexed (WDM) optical network such as optical power regulators, crossconnects, and add/drop multiplexers. We used a discrete array of 16 switch attenuators to implement a reconfigurable 16-channel 100-GHz spacing WDM drop module of an add/drop multiplexer. Thru-channel extinction was greater than 40 dB and average insertion loss was 21 dB. Both drop-and-transmit of multiple channels (11-18-dB contrast, 14-19-dB insertion loss) and drop-and-detect of single channels (>20-dB adjacent channel rejection, 10-14-dB insertion loss) were demonstrated     

光路插入式测量法及其应用

提出光路插入式测量法,用于解决光通信实际应用中,由于测量端口接插磨损和仪表标校问题而产生的附加静态和动态测量误差;通过对标称尾纤插入损耗的对比测量,证明光路插入式测量法的测量精度达到仪表的原始标称测量精度;应用光路插入式测量法测量当前光通信网中大量使用的光分路器样本,通过光分路器插入损耗的温度稳定性,通道均匀性和产品一致性的测量分析,验证光路插入式测量法能有效避开仪表标校、端口接插磨损产生的静态和动态测量误差,具有较好的实用性。     

Fiber-optic tactile microsensor for detecting the position of thetip of a fiberscope

A tactile microsensor employing optical fibers has been developed and evaluated. The sensor is used for touch sensing to detect the position of the tip of a fiberscope inside a small tubule, such as a blood vessel. The sensor consists of bosses as feelers, which are split sections of the end of a polyurethane tube, a metal diaphragm as a mirror and optical fibers transmit light. The sensors are fabricated using silicon micromachining, such as anisotropic etching and excimer laser etching. The sensing principle is based on the detection of changes in optical reflective intensity from a diaphragm located between a boss and an optical fiber. The width and height of the boss are both 200 μm. For the transmitting source and signal light, a multimode optical fiber 50/125 μm (core/clad) in diameter is used. The results show that tactility measurements can be made easily and safely in blood vessels. This paper describes the structure, fabrication processes, and performance of the sensor. We also propose micromeasuring systems combined with the tactile sensor and a fiberscope of contact type     

一种推力轴承油膜厚度光纤传感器的网络补偿技术

本文在光纤传感补偿网络基础理论的启发下，应用了一种基于压力油介质影响因子的三节点全光纤补偿网络结构，建立了一种新型油膜厚度光纤传感器网络补偿数学模型。实测应用表明：该补偿网络结构与巳有的其它网络相比，具有性能优良、结构简单、容易实现的特点，进一步提高了油膜厚度光纤传感器的测量精度。     

Polymeric optical waveguide films for short-distance opticalinterconnects

We describe three different applications of polymeric waveguide films as short-distance optical interconnects. We fabricated the waveguide films, which were 6.5 cm long and mounted in MT-compatible (MTC) connectors by passive alignment, for MM fiber systems with a 50-μm diameter graded index (GI) core. The average insertion loss of these devices was approximately 0.6 dB at 0.85-μm wavelength. We also fabricated waveguide films with a 350 mirror and an MTC connector for use as 90° out-of-plane optical deflectors, and they exhibited an insertion loss of 1 dB. Two silica planar waveguides for single-mode (SM) fiber systems were also connected by a polymeric waveguide film. Low insertion losses were obtained in both MM and SM films designed to be employed as bending waveguides. This reveals their good potential for use as practical short-distance optical interconnects     

粗糙度光纤传感器的理论与实践

本文对粗糙度光纤传感器进行了理论分析与实验研究。首先,提出了光纤传感器传递函数和表面粗糙度传递函数的概念,明确了有关的各参量之间的定量关系,得到了利用光纤传感器进行粗糙度测量数学表达式,为粗糙度光纤传感器的设计提供了理论依据。在这种理论指导下设计出的光纤传感器探头具有结构合理、操作方便、测量快速、无损测量、成本低廉等优点。最后本文还对实用化中的一些问题及解决措施提出了某些新观点。     

Development of long range optical fiber sensors for compositesubmarine power cable maintenance

Long range optical fiber sensors for power cable maintenance have been incorporated into a newly developed 500 kV DC submarine power cable. Optical fibers are used for a distributed temperature sensor and a mechanical damage sensor. The distributed temperature sensor provides data on temperature at distances up to 30 km, and the mechanical damage sensor locates external damage points on the submarine cable. After each characteristic was investigated, optical fiber sensors were incorporated on the submarine power cable. This composite cable was evaluated by various mechanical tests. The results were satisfactory and showed the composite cable to be of practical use. This new approach of incorporating optical fiber sensors in the cable structure brings a new sophistication and reliability to cable maintenance