分立式与分布式光纤传感关键技术研究进展

光纤传感技术已广泛应用于航空航天、石油化工、电子电力、土木工程、生物医药等领域,其技术形式主要体现为分立式和分布式.分立式光纤传感技术利用光纤敏感器件作为传感器来感知被测参量的变化,光纤作为光信号的传输通道连接光纤传感器及后端的解调装置;分布式光纤传感系统基于光纤瑞利散射、拉曼散射或布里渊散射等光学效应,利用光纤本身作为传感器,可对沿途的光信号进行大范围、长距离传感.本文介绍了分立式与分布式光纤传感中主要关键技术的研究进展,并对未来的研究和发展方向进行了探讨.     

微结构光纤传感器设计的新进展

根据导光机理、微孔分布、介质载入、纤芯数量及对称性等因素,对微结构光纤进行了具体分类。在此基础上,阐述了微结构光纤传感器的结构设计方法。对近年来国内外(包括作者设计)的典型微结构光纤传感器和微结构光纤光栅传感器进行了详细介绍和综合评述,对基于微结构光纤及微结构光纤光栅的新型传感器的发展进行了展望。     

微结构光纤传感器设计的新进展

根据导光机理、微孔分布、介质载入、纤芯数量及对称性等因素,对微结构光纤进行了具体分类。在此基础上,阐述了微结构光纤传感器的结构设计方法。对近年来国内外(包括作者设计)的典型微结构光纤传感器和微结构光纤光栅传感器进行了详细介绍和综合评述,对基于微结构光纤及微结构光纤光栅的新型传感器的发展进行了展望。     

基于光纤微结构加工和敏感材料物理融合的光纤传感技术

将功能敏感材料与光纤在物理层面进行有机融合,充分发挥光纤传感器在结构集成、材料集成等方面的优势,将有望发展新型的光纤传感器件和系统.本文综述了飞秒激光光纤微加工技术分别在标准的单模光纤和光纤光栅上制备微结构,再结合敏感材料制备技术,实现在物理层面上光纤传感器材料和结构的集成和融合,探索实现新型高性能的光纤传感新技术.     

S型光纤锥的研究进展

随着新型微加工工艺的发展,传统的锥型光纤发展派生出数千种不同的微结构光纤.其中,S型光纤锥由于其体积小、质量轻、抗电磁干扰以及可以直接嵌入结构化系统的灵活性得到了迅猛地发展.随着对S型光纤锥研究的深入,基于S锥的各种结构和功能的光纤传感器不断地被提出,用于测量温度、应变、折射率、湿度和磁场等,不仅丰富了光纤传感器的种类,更加深了人们对传感机理的认识.本文全面回顾了S型光纤锥的研究进展,包括传感原理、制备方法、各种传感结构组合以及传感应用等,并对其发展进行了展望.     

基于微波光子学的准分布式光纤传感解调技术

准分布式光纤传感系统在土木工程、能源勘测、航空航天、国防、化工等领域一直发挥着不可替代的重要作用。以微波光子学为基础的准分布式光纤传感解调技术被广泛应用于光纤复用系统的快速、高精度的信号解调与传感器定位。与传统的光学波长解调方案相比,该技术大幅提高了系统的解调速率,弥补了传统解调方法在传感器定位方面的缺陷。本文主要介绍了近年来国内外在基于微波光子学的准分布式光纤传感解调领域的研究进展,从光纤光栅准分布式传感系统和光纤法布里-珀罗准分布式传感系统两方面入手,对比分析了现有的数种微波解调光纤准分布式系统的优缺点,并对基于微波光子学的准分布式光纤传感解调技术的未来发展方向进行了总结与展望。     

基于银纳米线的类熊猫型微结构光纤传感器

设计了基于银纳米线等离子体共振效应的大孔径微流通道的类熊猫型微结构光纤传感器,采用全矢量有限元法对该传感器进行了数值研究,讨论了待测液折射率等参数对光纤传感器的损耗和灵敏度的影响。结果表明:随着待测液折射率和银纳米线直径的增大,损耗和光谱峰值λpeak都将增大;并且当银纳米线的直径增加到一定程度时,损耗和灵敏度都会呈现多峰值现象。最后取银纳米线直径d=150 nm,得到最大幅度灵敏度为910 dB/RIU,最大光谱灵敏度为1 400 nm/RIU。     

红外硫系微结构光纤的研究进展

硫系微结构光纤结合了红外硫系玻璃和微结构光纤的优点,在红外指纹区内分子结构鉴别、痕量气体检测、深空探测、红外激光传输等领域具有重大应用价值.本文从结构分类、应用特点和制备技术三方面,对目前红外硫系微结构光纤的研究进展进行了逐一介绍,并对硫系微结构光纤的未来发展进行了展望.     

保偏微结构光纤啁啾光栅折射率传感特性分析

将有限元法和传输矩阵法相结合,系统地研究了保偏微结构光纤(PM-MOF)啁啾布拉格光栅的折射率传感特性。仿真研究了光纤空气孔中充入不同折射率被测物时啁啾光栅的反射谱,结果表明随着被测物折射率的增加,反射谱的面积出现明显变化,由此得到了光栅反射谱面积与被测物折射率的关系。分析了中心孔直径、啁啾系数、切趾函数等光栅结构参数对反射谱的影响。分析表明由于光纤两个方向的偏振模对温度、噪声等干扰响应相似,因此利用两个偏振模式反射谱的相对变化进行监测能够有效地降低干扰,提高传感器的稳定性;其次,由于反射谱面积正比于光强,这一方法将光栅的光谱解调转化为光强解调,简化了解调系统,便于现场实时测量。研究结果为保偏微结构光纤光栅在折射率传感器及其生物传感器方面的应用提供了理论依据。     

基于薄芯光纤模态干涉技术的折射率 传感特性实验研究

报道了一种具有微结构缺陷的折射率传感器,并对其折射率特性进行了实验研究.将一部分薄芯光纤熔接于标准单模光纤中,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仪.通过减小薄芯光纤的包层直径,以增强包层中的传输模在环境中的倏逝场,从而提高对环境折射率测量的灵敏度.实验表明,该折射率传感器具有损耗低、成本低、灵敏度高和线性度好等特点.     

A fiber-optic voltage sensor based on macrobending structure

We propose and demonstrate an optical voltage sensing scheme based on a macrobending optical fiber in a ratiometric power measurement system. This novel approach to sensing has not been utilized before and has the advantage that the sensor involves simple fabrication compared to existing fiber-optic voltage sensors. To prove the feasibility of such a fiber-optic sensor, a sensor for a voltage range from 0∼100 V is demonstrated, with a resolution of 0.5 V. The sensor is robust, linear, and shows a competitive measurement resolution. The sensor can be easily scaled to suit other voltage levels and be effectively combined with optical current sensors.     

Low-Temperature Radiometric Measurements Using a Silver Halide Optical Fiber and Infrared Optical Devices

In this study, we measured an infrared radiation which is transferred by a silver halide optical fiber from a heat source using a radiometer system for low-temperature measurements. To increase the amount of infrared radiation through the silver halide optical fiber and to the pyroelectric sensor, infrared optical devices used were an infrared focusing lens and a collimator. The relationship between the temperatures of a heat source and the measured radiometer signals were determined. The measurable temperature range of a fiber-optic temperature sensor using a pyroelectric sensor was from 298 to 333 K. It is expected that a noncontact low-temperature sensor using an infrared optical fiber can be developed for medical and industrial usages based on the results of this study.     

基于Mach-Zehnder干涉仪的单模光纤声波传感器的研究

光纤传感器是20世纪70年代中期发展起来的一种新型传感器.它与普通的传感器相比,具有灵敏度高、抗电磁干扰、耐腐蚀、防燃等优点,因此在温度、应力、磁场等传感领域都有着广泛的应用.本文研究的光纤声波传感器,其基础为Mach-Zehnder(M-Z)全光纤干涉仪,我们主要的工作集中在传感臂探头的制作.所研制的基于M-Z干涉仪...     

基于纳米覆膜光纤F-P传感器的折射率光谱特性

采用层层组装和化学共价交联的方法对光纤Fabry-Perot (F-P)干涉传感器的端面进行了纳米聚电介质覆膜修饰,并实验研究了覆膜后传感器的折射率响应光谱特性。选择聚二甲基二烯丙基氯化铵(PDDA)和聚苯乙烯磺酸钠(PSS)为纳米覆膜材料,随着覆膜层数的增加,光纤F-P传感器的反射谱对比度呈现由高到低,再到高的规律,且反射谱对比度具有良好的温度稳定性。选取覆膜层数为20双层的光纤F-P传感器对一系列浓度的蔗糖和无机溶液进行了折射率光谱响应测试,实验测得折射率检测拐点由1.457延伸至1.4623,对低折射率物质的折射率灵敏度为24.53 dB·RI-1,对高折射率物质的折射率灵敏度为3.60 dB·RI-1,且均具有良好的线性。研究结果为光纤F-P传感器对低折射率物质的功能化检测提供了新方法。     

Infrared radiation thermometer using a silver halide optical fiber for thermal ablation

In this study, we have fabricated non-contact temperature sensor using an infrared optical fiber for measuring temperature distributions during radiofrequency ablation. We have measured an infrared radiation, which is transferred by a silver halide optical fiber from the multi-points on the water around inserted electrode, using a thermopile sensor and the output voltages of a thermopile sensor are compared with those of the thermocouple recorder. Also, the relationship between the temperatures and the output voltages of a thermopile sensor at the measuring points is determined to obtain the temperature distribution. The measurable temperature range of a fiber-optic non-contact temperature sensor is from 37 to 80 °C.     

Development of One-dimensional Fiber-Optic Radiation Sensor for Measuring Dose Distributions of High Energy Photon Beams

The purpose of this study was to develop a method for measuring the one-dimensional dose distribution of a high-energy photon beam using a miniaturized high-resolution fiber-optic radiation sensor array. The measurements were made by thin plastic optical fibers with organic scintillating fiber sensor probes that emit the visible wavelength of light. The scintillating light is guided to a silicon photodiode array by plastic optical fibers in order to convert light output to an electrical signal. The one-dimensional spatial dependence of photon beam is measured by a one-dimensional fiberoptic sensor array in a poly(methyl methacrylate) (PMMA) phantom. It is shown that this fiber-optic radiation sensor has better spatial resolution than a conventional ionization chamber and much less time is required to measure one-dimensional dose distribution in the high radiation fields. The real-time and the high spatial resolution measurements due to the small detector volume make this system suitable for dosimetry in radiation therapy.     

Fiber-optic refractive-index sensors based on transmissive and reflective thin-core fiber modal interferometers

We present a new fiber-optic refractive-index sensor based on a fiber modal interferometer constituted by a thin-core optical fiber, whose cut-off wavelength is around three times shorter than normal single-mode fiber. In such a core diameter mismatching structure, the high-order cladding modes are efficiently excited and interfere with the core mode to form a high extinction-ratio filter (>30 dB). Both transmissive and reflective thin-core fiber modal interferometers are experimentally demonstrated, and show a high sensitivity to a small change of external refractive-index (>100 nm/R.I.U.), but a low sensitivity to the change of temperature (<0.015 nm/°C). Such a fiber device possesses an extremely simple structure, but excellent refractive-index sensing properties, and thus is an ideal candidate for fiber-optic biochemical sensing applications.     

On the possible use of optical fiber Bragg gratings as strain sensors for geodynamical monitoring

Optical fiber sensors can be used to measure many different parameters including strain, temperature, pressure, displacement, electrical field, refractive index, rotation, position and vibrations. Among a variety of fiber sensors, fiber Bragg gratings (FBG) have numerous advantages over other optical fiber sensors. One of the major advantages of this type of sensors is attributed to wavelength-encoded information given by the Bragg grating. Since the wavelength is an absolute parameter, signal from FBG may be processed such that its information remains immune to power fluctuations along the optical path. This inherent characteristic makes the FBG sensors very attractive for application in harsh environments, “smart structures” and on-site measurements.This paper reviews the achievements about the FBG as a strain and temperature sensor and describes the potential applications of FBG sensors for applications in the field of geophysics and its expected development in the near future. The applications could include: rock deformation, fiber-optic geophone, optical based seismograph, vertical seismic profiling and structural monitoring of civil structures. Different techniques to detect strains and various applications will be reviewed and discussed. The problem of temperature–strain cross sensitivity, that is particularly difficult to eliminate, is addressed and approaches to overcome it are discussed.     

分布式光纤温度传感器的研究现状及发展

本文描述了光纤的特点及点式光纤温度传感器与几种分布式光纤温度传感器的研究现状,并指出了后者的发展方向.