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为了满足复杂的工程现场环境对相敏光时域反射仪(φ-OTDR)的各项性能指标的需求,提出基于自适应卡尔曼滤波(AKF)和频分复用(FDM)的高性能φ-OTDR,利用FDM提升系统的频响带宽,引入AKF对线性响应于外界振动的相位状态的噪声统计特性进行实时估计和修正,抑制了衰落和串扰导致的相位失真。实验结果表明,改进后φ-OTDR系统的传感线性度被有效提升,系统本底噪声降低到-83.7dB2/Hz,应变分辨率达到了0.28pε/Hz1/2。 相似文献
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干涉型光纤传感技术研究 总被引:1,自引:1,他引:0
我们研究了利用零差检测技术的光纤Mach-Zehnder干涉仪,相位检测灵敏度达到了2.8×10~(-4)rad。本文将叙述光干涉相位检测的基本原理、实验装置及结果分析。 相似文献
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In this paper,the waveforms in time domain and frequency domain of two kinds of optical frequency domain reflectometry (OFDR) sensing systems are compared,which use common fiber Bragg grating (FBG) and... 相似文献
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Phase-sensitive optical time-domain reflectometry (Φ-OTDR) has attracted numerous attention due to its superior per-formance in detecting the weak perturbations... 相似文献
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相位敏感光时域反射系统以其分布式光纤传感技术的优势在分布式水听、压裂微地震检测、自然灾害预警等低频监测领域具有极高的应用前景。文中对系统中脉冲斩波信号与频率调制信号时钟不同源的问题予以验证,并对其产生的影响进行理论分析;设计双路同步时钟源驱动产生脉冲斩波信号和频率调制信号,降低每个脉冲重复周期中频率调制信号的随机低频相位噪声,提高探测脉冲光的相位稳定性;采用时钟同源和时钟非同源两种方式对典型的基于外差相干检测的相位敏感光时域反射系统的声光调制器进行驱动,由信号发生器驱动缠有光纤的压电陶瓷,产生不同频段的扰动信号。实验结果表明:在同一测试条件下,前者在低频段的信噪比、相位解调质量、频率响应方面均优于后者,最小响应频率为0.1 Hz,相对提高两个数量级,降低了系统中低频噪声干扰。该方法易于实现,可与现有的低频性能优化方法或结构兼容,进一步提高系统低频响应性能。 相似文献
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C.J.S. de Matos J.R. Taylor 《Photonics Technology Letters, IEEE》2003,15(8):1064-1066
Optical time-domain reflectometry is proposed and demonstrated as a means to characterize the signal power evolution in discrete fiber Raman amplifiers. Up to /spl sim/20-dB-gain amplifiers have been characterized comprising different fibers, under copropagating and counterpropagating signal-pump configurations, and under saturated and unsaturated conditions. The results demonstrate the flexibility of this simple and useful amplifier characterization technique. Simulations show good agreement with experimental results, and sustain the reliability of the technique. 相似文献
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We report an optical time-domain reflectometer that employs an ultrafast optical switch based on nondegenerate four-wave mixing in a semiconductor laser amplifier. Two-point spatial resolution on the order of 1 mm over 2 m is demonstrated; Fresnel reflections with optical return losses greater than 53 dB are detected. Submillimeter-resolution optical time-domain reflectometry over a 100-m range should be possible with modifications to the pulse sources 相似文献
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Luc THVENAZ 《中国光电子学前沿》2010,3(1)
Optical fiber sensors based on stimulated Brillouin scattering have now clearly demonstrated their excellent capability for long-range distributed strain and temperature measurements. The fiber is used as sensing element, and a value for temperature and/or strain can be obtained from any point along the fiber. After explaining the principle and presenting the standard implementation, the latest developments in this class of sensors will be introduced, such as the possibility to measure with a spatial resolution of 10 cm and below while preserving the full accuracy on the determination of temperature and strain. 相似文献
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The technique of polarisation optical time-domain reflectometry has been used to measure magnetic field through the use of the Faraday effect. A spatial resolution of 0.4 m was achieved, and a sensitivity corresponding to a magnetic field of 10?3 T over a length of 0.5 m was obtained. 相似文献
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根据受激布里渊散射(SBS)对相位敏感光时域反射计(-OTDR)的监测距离的限制,分析了在使用不同灵敏度的光电探测器时-OTDR系统的监测距离,并根据SBS阈值随着光纤长度的增加而下降的特点,提出了一种新的光路结构以提升系统的监测距离。该光路结构采用环行器将敏感光纤分为多个部分,并对各部分的后向瑞利散射光分别进行探测,避免了各部分光纤产生的斯托克斯光相互叠加,从而提高了SBS阈值,进而实现了提升系统监测距离的目的。在实验室测试中,使用3个环行器将敏感光纤分为了3个部分并实现了66.92 km的监测距离。通过增加环行器的数量,系统的监测距离可以进一步提高。 相似文献
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The use of optical time-domain reflectometry (OTDR) on long-span fiber transmission systems containing in-line optical amplifiers is discussed. Having identified the specific requirements for OTDR equipment, measurements were carried out on systems of up to 300 km in length, containing three semiconductor laser amplifiers. The results demonstrate that OTDR can be used not only for fault location on fiber links several hundred kilometers in length but also as an alternative to standard system supervisory techniques, thus providing the potential for minimizing the hardware in the optical amplifier stages of future long-span fiber optic transmission systems 相似文献
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为了提高光纤光栅(FBG)传感系统的传感容量以及传感器的实际工程生存能力和后期可维护性,提出了一种基于光频域反射(OFDR)技术的总线型拓扑结构的FBG传感系统。利用OFDR技术,采用相同波长的FBG传感器,克服了光源带宽对系统传感容量的限制,极大提高了系统的传感器复用能力和空间分辨率。与传统的采用弱反射率FBG串联组网相比,本文系统采用强反射率FBG和光分路器实现总线型拓扑结构,在提高传感器的生存能力的同时,克服了串接式FBG传感网络中存在的多重反射和光谱阴影对测量精度的影响。温度实验表明,系统的波长重复性为±4pm。 相似文献