共查询到20条相似文献,搜索用时 0 毫秒
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介绍了各种光纤器件(光无源器件、有源器件、光纤集成器件等)回波损耗的测量原理和测量方法。提出了一些关键技术的解决方法和试验方案。对各种不确定因素进行了分析和试验验证,最终建立了一套光纤器件回波损耗测量装置。 相似文献
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Shenfang YUAN Rui HUANG YunjiangAeronautic Key Laboratory for Smart Materials Structures Nanjing University of Aeronautics Astronautics Nanjing ChinaKey Laboratory of Optoelectronic Technology Systems of the Ministry of Education Chongqing University Chongqing China 《材料科学技术学报》2004,20(2):199-202
3D braided composite technology has stimulated a great deal of interest in the world at large. But due to the three-dimensional nature of these kinds of composites, coupled with the shortcomings of currently-adopted experimental test methods, it is difficult to measure the internal parameters of this materials, hence causes it difficult to understand the material performance. A new method is introduced herein to measure the internal strain of braided composite materials using co-braided fiber optic sensors. Two kinds of fiber optic sensors are co-braided into 3D braided composites to measure internal strain. One of these is the Fabry-Parrot (F-P) fiber optic sensor; the other is the polarimetric fiber optic sensor. Experiments are conducted to measure internal strain under tension, bending and thermal environments in the 3D carbon fiber braided composite specimens, both locally and globally. Experimental results show that multiple fiber optic sensors can be braided into the 3D braided composites to meas 相似文献
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Two types of CdTe quantum dots of different sizes (4 and 5 nm) were successfully deposited on optical fibers using the layer-by-layer electrostatic self-assembly method. The sensors showed a linear and reversible variation of the emission wavelength for a temperature range from 30 degC to 100 degC, with a sensitivity of 0.2 nm/degC 相似文献
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Polymer Optical Fiber Sensors for Distributed Strain Measurement and Application in Structural Health Monitoring 总被引:1,自引:0,他引:1
Liehr S. Lenke P. Wendt M. Krebber K. Seeger M. Thiele E. Metschies H. Gebreselassie B. Munich J.C. 《IEEE sensors journal》2009,9(11):1330-1338
Polymer optical fiber (POF) sensors have the unique ability to measure high strain distributed along the fiber up to 40% using the optical time-domain reflectometry (OTDR) technique. Both, standard PMMA fibers and perfluorinated (PF) graded-index (GI) POF are introduced and evaluated in potential use and applicability. Further, distributed length change measurement based on cross-correlation analysis of the characteristic fiber signature of PF POF is introduced. We conclude the advances in distributed POF strain sensors technology with respect to application in structural health monitoring. Special focus is on the sensor integration into technical textiles for health monitoring of geotechnical structures and masonry structures. Measurement results of sensor-equipped textiles in different model tests are presented, displacement of soil and cracks in retrofitted masonry structures are detected and evaluated. 相似文献
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Consales M. Crescitelli A. Campopiano S. Cutolo A. Penza M. Aversa P. Giordano M. Cusano A. 《IEEE sensors journal》2007,7(7):1004-1005
In this letter, the possibility to use single-walled carbon nanotubes (SWCNTs) as sensitive nanostructured material for the development of an optoelectronic sensor that can perform chemical detection in water has been investigated and demonstrated for the first time. The fabricated sensor has been employed in a reflectometric system involving single wavelength reflectance measurements. The good stability of the steady-state signal, the high sensitivity, as well as the good response dynamics obtained in the case of toluene detection confirm the potentiality of SWCNTs to be employed in a water environment. 相似文献
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The fiber optic sensor (FOS) embedded perpendicular to reinforcing fibers causes an `Eye' shaped defect. The length is about 16 times fiber optic radius (RFos) and height is about 2RFos. The eye contains fiber optics in the center surrounded by an elongated resin pocket. Embedding FOS causes geometric distortion of the reinforcing fiber over a height equal to 6 to 8 RFos. This defect causes severe stress concentration at the root of the resin pocket, the interface (in the composite) between the optical fiber and the composite, and at 90° to load direction in the composite. The stress concentration was calculated by finite element modeling of a representative micrograph. The FE results agreed reasonably with analytical and experimental data in the literature for a similar problem. The stress concentration in axial direction was about 1.44 and in transverse direction at the interface was -0.165 and at resin pocket was 0.171. Under tensile loading, the initial failure was by transverse matrix cracking (fiber splitting) at the root of the resin pocket, then that lead to final fracture by fiber breakage. Under compression loading, the failure initiation was by interfacial cracking due to large transverse tensile stress and the final fracture was by compression. Fracture stress calculated from the analysis using the maximum stress criteria agreed reasonably with test data. 相似文献
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开发了一种用采脉冲氙灯光源照明,多元阵列光纤作为多通道接收器的光纤型脉冲多通道快速分光颜色测量系统。该仪器的色分辨率高,动态范围大,色品坐标精度为0.002,测量光谱范围为380~780nm,光谱分辨率为10nm,测量时间几个毫秒,测量时间间间隔小于5s。它能测量较暗物体和荧光物体的颜色,也能进行脉冲光源的相对光谱功率分布的测量,并能给出各种标准照明体和各种色度系统下的色度参数。 相似文献
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This paper gives a review of acoustic and ultrasonic optical fiber sensors (OFSs). The review covers optical fiber sensing methods for detecting dynamic strain signals, including general sound and acoustic signals, high-frequency signals, i.e., ultrasonic/ultrasound, and other signals such as acoustic emissions, and impact induced dynamic strain. Several optical fiber sensing methods are included, in an attempted to summarize the majority of optical fiber sensing methods used to date. The OFS include single fiber sensors and optical fiber devices, fiber-optic interferometers, and fiber Bragg gratings (FBGs). The single fiber and fiber device sensors include optical fiber couplers, microbend sensors, refraction-based sensors, and other extrinsic intensity sensors. The optical fiber interferometers include Michelson, Mach-Zehnder, Fabry-Perot, Sagnac interferometers, as well as polarization and model interference. The specific applications addressed in this review include optical fiber hydrophones, biomedical sensors, and sensors for nondestructive evaluation and structural health monitoring. Future directions are outlined and proposed for acousto-ultrasonic OFS. 相似文献
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《IEEE sensors journal》2009,9(6):635-640
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提出了一种基于高斯光脉冲延迟技术的无盲区、高精度光纤长度测量方法。借助光纤延迟环的作用,在高速示波器上可以观察两路具有相对时延的高斯脉冲序列。通过调节脉冲频率可使两路高斯脉冲完全重合,依据此时脉冲频率可计算出光纤长度。脉冲未完全重合则会引入频率测量的误差,而利用脉冲时延与幅度的转换关系,通过脉冲幅度极大值的测量可以精确判断脉冲是否重合。脉冲频率的分辨力达到0.1 Hz,从而提高光纤长度测量的精确度。实验中当光源波长为1296nm时,该方法测量2284.34m G.652单模光纤长度的不确定度为0.04m,测量12726.57m的不确定度为0.24m。 相似文献
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Puangmali P. Althoefer K. Seneviratne L. D. 《IEEE transactions on instrumentation and measurement》2010,59(2):283-291
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Perez-Herrera R.A. Frazao O. Santos J.L. Araujo F.M. Ferreira L.A. Baptista J.M. Lopez-Amo M. 《IEEE sensors journal》2009,9(12):1647-1653
We report on the use of erbium doped fiber (EDF) amplification to enhance a frequency modulated continuous wave (FMCW) technique for referencing optical intensity sensors located between two Bragg grating structures. The experiment combines the concept of FMCW with the spectrally selective mirror properties of Bragg gratings to interrogate with referencing properties intensity based sensors. The interrogation system without amplification yields a sensor resolution of around 0.078 dB. When the EDF amplifier is introduced into the experimental set up, the sensor sensitivity does not change, but the signal-to-noise ratio is improved, resulting into an enhanced resolution of 0.025 dB. We also obtain a remote sensing operation at a location of 50 km, showing the feasibility of this configuration to be used as a remote sensing application. 相似文献
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光纤化学传感器的研究及其在环境分析中的应用 总被引:1,自引:0,他引:1
本文综述了光纤化学传感器的特点、工作原理、类型及各类光纤化学传感器(气敏、pH、金属离子和有机化合物等)的研究进展及其在环境分析中的应用,分析了近年来光纤化学传感器的技术发展和应用趋势。 相似文献
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Delepine-Lesoille S. Merliot E. Gautier Y. Quetel L. Delaveau M. Courteville A. 《IEEE sensors journal》2008,8(7):1145-1151
We present a novel concept of quasi-distributed flexible optical fiber extensometers fully compensated from thermal variations. Developed for structural health monitoring applications, the sensors are composed of a combination of intrinsic Fabry-Perot cavities as long-base extensometers, and point-like Bragg gratings inserted along the same fiber used as temperature sensors. This configuration enables a high degree of multiplexing, thus quasi-distributed sensing, and very efficient temperature compensation. Both types of sensors are read by a fiber-optic low-coherence interferometer, used in an original way to measure simultaneously the length variations of the cavities and the wavelength shifts of the Bragg gratings. Finally, we present the experimental validation of the whole measurement system, suitable for concrete structures instrumentation, as it includes an original optical fiber sheath packaging the optical fiber as a flexible sensor. 相似文献
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分布式光纤光子传感器与测量网络的进展 总被引:2,自引:1,他引:2
本文介绍了分布式光纤光子传感器与测量网络 (DOFPSMN)的发展历史 ,系统的工作原理、系统的结构 ,硬件和软件的组成 ,国内外分布式光纤光子传感器与测量网络的研究现状和技术水平 ,应用前景和发展方向 相似文献
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从光纤温度传感器出生,并在我们长期实验的基础上,分析了大多数光纤传感器难以走向实用化的原因,并提出了一定的处理方法和建议。我们认为,光纤传感器在推广应用上受到制约的重要原因是其长期稳定性和可靠性存在着问题,影响稳定性和可靠性的两个主要因素是光源输出光功率的漂移和光纤保护层的老化,尤其是位于待测区域的探头、敏感光纤和接续光纤的保护层老化问题限制了光纤传感器的应用。 相似文献