一种新型光纤法布里-珀罗应变干涉仪

论述了一种非本征法布里 珀罗光纤应变传感器。采用透明弹性聚合物薄膜作为法布里 珀罗干涉腔,聚合物固定在多膜光纤末端作为应变敏感元件。传感器的分辨率为2μm,测量精度在0～5000μm范围内为5μm。     

High spatial resolution distributed strain sensor based on linear chirped fiber Bragg grating and fiber loop ringdown spectroscopy

A simple sensor system for high spatial resolution distributed strain field measurement is proposed and demonstrated experimentally. The fiber loop ringdown technique combined with a linear chirped fiber Bragg grating is used to realize the high spatial resolution. A proof-of-concept distributed strain sensor with 2?mm spatial resolution is realized. The sensor network is also explored and researched experimentally. The proposed technique suggests a broad range of applications for real-time distributed physical parameter sensing, such as strain or temperature.     

一种新的白光光纤传感系统波长解调方法

提出了一种新的白光非本征法布里-珀罗干涉（EFPI）光纤传感系统的干涉谱处理方法,在白光法布里-珀罗干涉光纤传感系统中,一个中心波长为850nm的发光二极管（LED）作为宽谱光源,HR2000高分辨力微型光谱仪用来测量返回的干涉光谱。通过跟踪干涉光谱中的特定谱峰点,法布里-珀罗干涉传感器的腔长值可以被解调出来。应用反向传播神经网络,解决了单峰测量方式的级次模糊问题。反向传播神经网络能够分辨出干涉谱中不同谱峰的干涉级次,因而可以进行多个谱峰的连续跟踪。从而实现了高精密度、大动态范围的测量。进行了基于这种干涉谱处理方法的白光法布里-珀罗干涉传感系统的应变测量实验。利用该传感系统实现了精密度达0．1με,500με范围的应变测量。     

A novel fiber Bragg grating high-temperature sensor

A novel fiber Bragg grating (FBG) sensor for the measurement of high temperature is proposed and experimentally demonstrated. The interrogation system of the sensor system is simple, low cost but effective. The sensor head is comprised of one FBG and two metal rods. The lengths of the rods are different from each other. The coefficients of thermal expansion of the rods are also different from each other. The FBG will be strained by the sensor head when the temperature to be measured changes. The temperature is measured basis of the wavelength shifts of the FBG induced by strain. A dynamic range of 0–800 °C and a resolution of 1 °C have been obtained by the sensor system. The experiment results agree with theoretical analyses.     

基于新型长周期光纤光栅的低成本应变传感系统

首次利用高频CO2激光脉冲写入的长周期光纤光栅的边缘滤波效应，实现了静态与动态应变的测量.使用单波长输入光，光信号经过长周期光纤光栅衰减后进入光电探测器，最终输出电压信号.当对光栅施加应变时，其中心波长将发生漂移，由于光栅阻带的边缘滤波效应，光电探测器接收的光强会随之变化，测量其输出的电信号，可以得出光栅发生的应变大小与频率.对于静态应变测量，可分辨的最小应变小于10 με，精度为±10 με;在动态实验中,发现光栅能够响应5 kHz以上的动态应变.这种传感系统结构简单，成本低,响应快.     

Dynamic strain measurement using two wavelength-matched fiber Bragg grating sensors interrogated by a cascaded long-period fiber grating

In this work, we describe a fiber Bragg grating (FBG) sensing system using two wavelength-matched FBG sensors for static and dynamic strain measurement. A cascaded long-period fiber grating (CLPG)-based demodulation technique has been used to interrogate the two wavelength-matched FBG sensors. Experimental results of static strain measurement show that the proposed system has a strain resolution of 1 με. This system has also been used for dynamic strain measurement. An eddy current displacement meter-based system has been used as a comparison measurement. Experimental results of dynamic strain measurement have proved that the FBG sensing system has a good performance in the measurement of dynamic strain. The results of static and dynamic strain measurement indicate that the sensing system using two wavelength-matched FBG sensors is superior to the single FBG sensor system.     

Distributed strain sensor based on dynamic grating in polarization-maintaining erbium-doped fiber

A novel distributed fiber-optic strain sensor based on dynamic grating in polarization-maintaining erbium-doped fiber (PM-EDF) is demonstrated experimentally. The dynamic grating is written with light beams polarized along one primary polarization axis of the PM-EDF, and read with a light beam polarized along the other primary polarization axis. When a strain is applied to the fiber, the detected Bragg reflection frequency of the dynamic grating shifts in proportion to the birefringence change, which is proportional to the strain. By employing the technique of synthesis of optical coherence function, the dynamic grating is localized in a region that can be shifted to sweep along the fiber to determine the location of the strain. In the experiment, a spatial resolution of 20 cm is demonstrated.     

Fiber grating sensors for high-temperature measurement

Two fiber grating sensors for high-temperature measurements are proposed and experimentally demonstrated. The interrogation technologies of the sensor systems are all simple, low cost but effective. In the first sensor system, the sensor head is comprised of one fiber Bragg grating (FBG) and two metal rods. The lengths of the rods are different from each other. The coefficients of thermal expansion of the rods are also different from each other. The FBG will be strained by the sensor head when the temperature to be measured changes. The temperature is measured based on the wavelength-shifts of the FBG induced by the strain. In the second sensor system, a long-period fiber grating (LPG) is used as the high-temperature sensor head. The LPG is very-high-temperature stable CO₂-laser-induced grating and has a linear function of wavelength–temperature in the range of 0–800 °C. A dynamic range of 0–800 °C and a resolution of 1 °C have been obtained by either the first or the second sensor system. The experimental results agree with theoretical analyses.     

Simple design of optical fiber displacement sensor using a multimode fiber coupler

A simple design sensor is demonstrated using a fabricated multimode plastic fiber coupler in conjunction with reflective intensity modulation technique. The performances of this sensor are investigated for different light sources. This sensor uses only one fiber for sending and receiving the light and therefore only the back slope exists. The sensor shows the highest performance with the use of yellow light source, which has the highest intensity and the smallest beam divergence. The sensitivity, linear range, resolution and dynamic range of the sensor are obtained at 0.0001 mV/μm, 1500 μm, 70 μm, and 5.0 mm, respectively. The simplicity of the design, high degree of sensitivity, dynamic range and the low cost of the fabrication make it suitable for real field applications.     

基于银膜孔阵列超强透射效应的相敏表面等离子体共振传感器的仿真研究

A high spatial resolution, phase-sensitive Surface Plasmon Resonance（SPR） sensor based on Extraordinary Optical Transmission （EOT） is proposed to monitor the binding of organic and biological molecules to the silver surface. The 2D nanohole-array configuration is well suited ~br dense integration in a sensor chip. The optical geomeWy is collinear, which simplifies the alignment with respect to the traditional Kretschmann arrangement for SPR sensing. Various design parameters of the device have been studied by simulation. The heterodyne technique is used to improve the sensitivity. The optimization results indicate that the sensor has the advantages of achieving high resolution and a wide dynamic range simuhaneously.     

高分辨率CCD图像传感器及CCD摄像机的性能评价

研究了ＣＣＤ图像传感器及ＣＣＤ摄像机的性能及测试方法。重点探讨了高分辨率的ＣＣＤ摄像机的成像特点。论述了高分辨率ＣＣＤ图像传感器和高分辨率ＣＣＤ摄像机的性能。这些性能与当前厂商提供的商用ＣＣＤ摄像机有许多不同之处。评价高分辨率ＣＣＤ图像传感器的性能主要有灵敏度、动态范围、分辨率和拖影。评价高分辨率ＣＣＤ摄像机性能有灵敏度、最小照度、分辨率和光学格式等。给出了高分辨ＣＣＤ摄像机的性能评价实例,简述了其工艺特点和技术特点。     

基于2S2G棱镜的新型反向表面等离子共振生物传感器

提出了一种基于反向表面等离子体共振原理,由Ge_(20)Ga_5Sb_(10)S_(65)-钯-石墨烯分子-生物分子四层结构构成的新型生物传感器。当生物分子之间发生相互作用时,引起生物分子层折射率的变化,从而导致反向表面等离子体共振角的偏移。在此基础上,根据传输矩阵法推导了传感器的输出光谱,重点讨论了本文提出的传感器与传统传感器相比,在灵敏度、分辨率、动态检测范围以及检测信号信噪比方面取得的进展。另外,通过对比研究,深入分析了辅助介质层石墨烯厚度对传感器性能的影响。最后,利用近红外光作为提出的传感器的入射光,分析了在近红外区域传感器性能的改善。研究结果表明:单层石墨烯分子使传感器性能达到最佳;反向表面等离子共振峰强度约为入射光强的80%~90%,使传感器的输出信号具有较大的信噪比;在可见光区域,当入射光波长为632.8nm时,提出的反向表面等离子共振生物传感器的分辨率是基于SiO_2棱镜耦合反向表面等离子共振生物传感器的1.9倍,是传统表面等离子共振生物传感器的3.5倍,提出的传感器的动态检测范围约是现有传感器的2倍;利用Ge_(20)Ga_5Sb_(10)S_(65)棱镜可使反向表面等离子共振生物传感器检测光波长由可见光区域扩展到近红外区域,当入射光为1 000nm时,传感器的分辨率是可见光区域的3~4倍。该研究对基于反向表面等离子体共振原理生物传感器的实现与发展具有重要意义。     

Intrinsic fiber Fabry-Perot temperature sensor with fiber Bragg grating mirrors

A fiber Fabry-Perot interferometer (FFPI) sensor is formed with broadband (~3 nm, 3-dB bandwidth) fiber Bragg grating (FBG) mirrors. Repetitively modulating a distributed-feedback laser produces chirping that modulates the reflectance of the FFPI. Because the reflectance of the FBG mirrors varies with optical frequency, the fringes in the sensor reflectance modulation are distinguishable, making it possible to extend the sensor dynamic range versus that of a FFPI sensor with conventional wavelength-dependent mirrors. An ambient temperature is determined in the range from 25 to 170 degrees C with a resolution of 0.005 degrees C.     

High resolution temperature insensitive interrogation technique for FBG sensors

In this letter, we propose a high resolution temperature insensitive interrogation technique for FBG sensors where one FBG acts as an edge filter to interrogate a separate FBG sensor. A high resolution of better than 5 με in strain measurement range from 0 to 1100 με and the best resolution of better than 1 με were verified by experiments. An error of only ±2.2 με is achieved over a temperature range from 15 to 50 °C, indicating that this strain interrogation technique is temperature insensitive. Using an altered system configuration, the temperature was also measured simultaneously with a resolution better than 0.2 °C.     

Simultaneous strain and temperature measurement based on a photonic crystal fiber modal-interference interacting with a long period fiber grating

An alternative all-fiber sensor for simultaneous strain and temperature measurement based on a photonic crystal fiber (PCF) spliced between single-mode fibers cascaded with a long period grating (LPG) is proposed. By collapsing the air holes at two splicing regions along the PCF, a simple but effective modal-interference (MI) is occurred between the core and cladding modes of the PCF. Due to the different responses on the changes of strain and temperature on the MI and the cascaded LPG, the strain and temperature can be measured simultaneously. Experimental results show that the sensing resolution of 9.1 με in strain measurement is experimentally achieved over a range of 2640 με, while the temperature sensing resolution is 0.27 °C within a range of 30-100 °C.     

基于副载波调频技术的光纤光栅传感网络查询

分析了副载波调频技术用于光纤光栅阵列查询的基本原理。从理论上推算了系统的查询空间分辨率及查询范围,并结合波分复用技术进行了光纤光栅传感网络的地址查询演示实验,同时使用可调谐滤波器对每个光栅信号进行了解调。实验结果很好地说明了该查询方案的可行性,且在单个光栅上的被测应变与可调谐滤波器的控制电压呈较好的线性关系。该系统具备有查询由几百个FBG组成的传感网络的潜在能力。     

Fiber Bragg grating strain sensor based on fiber laser

A study on fiber Bragg grating (FBG) strain sensor, based on erbium-doped fiber (EDF) laser, is presented. A strain-sensing element, FBG, also acts as the lasing wavelength selecting component. When strain is applied on the FBG, the laser cavity loss changes, leading to a modification of the laser transient. Strain measurements are obtained in the time domain by simply measuring the EDF laser build-up time. Relative variation in the build-up time of up to 190%, for a strain range from 0 με to 2350 με, is achieved with a resolution corresponding to a strain of better than 2.35 με. This study demonstrates a novel fiber sensor concept and the technical feasibility to develop fiber strain measurement.     

Effect of metamaterial layer on optical surface plasmon resonance sensor

In this paper an optical surface plasmon resonance (SPR) sensor with metamaterial for four and five layered structure is studied. The numerical results presented in this paper leads to a significant properties of metamaterials in sensing field. Computed results of SPR sensors using metamaterial are compared with conventional optical SPR sensors for four and five layered structure. It is seen that wider dynamic range or effective range of measurable refractive index increases when metamaterial layer is used. It is also verified that SPR sensor with metamaterial layer can dramatically enhance the resolution and reduce the reflectivity compared with conventional SPR. Validity of the magnetic field results is proved on the basis of smooth match of the fields in the different layers of the proposed optical SPR sensor.     

Phase sensitive SPR sensor for wide dynamic range detection

Phase detection has been utilized to enhance the sensitivity of surface plasmon resonance (SPR) sensors for a long time. However, an inherent drawback for phase sensitive SPR sensors are their limited dynamic range, which has greatly hindered wide applications of such sensors. In this Letter, a design combining phase detection and angular interrogation has been proposed to provide an SPR sensor with both high sensitivity and wide dynamic range. As a result, a resolution of 2.2×10^-7?RIU with a dynamic range of over 0.06?RIU has been achieved simultaneously. An added advantage of this design is the flexibility for sensitivity and dynamic range adjustment.     

平面圆形膜片式光纤布拉格光栅温度补偿压强传感

报道了利用光纤布拉格光栅反射波谱带宽展宽技术实现温度补偿的压强传感新方案。结合平面圆形膜片应变调谐的特点,采用膜盒式结构,将光纤光栅中心对准平面圆形膜片零应变半径并沿径向粘贴,利用反射波谱带宽对应变敏感而对温度不敏感的特性解调压强,成功地实现了温度补偿的压强传感测量。基于光谱分析仪0.05nm的光谱分辨力,实验测得带宽随压强响应灵敏度为0.34nm/MPa,压强精度为±0.15MPa,压强测量范围为0~7.5MPa。实验结果与理论分析基本一致。