- 标题
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Recent Advances in Brillouin Optical Correlation-Domain Reflectometry
摘要： Distributed ?ber-optic sensing based on Brillouin scattering has been extensively studied and many con?gurations have been developed so far. In this paper, we review the recent advances in Brillouin optical correlation-domain re?ectometry (BOCDR), which is known as a unique technique with intrinsic single-end accessibility, high spatial resolution, and cost ef?ciency. We brie?y discuss the advantages and disadvantages of BOCDR over other Brillouin-based distributed sensing techniques, and present the fundamental principle and properties of BOCDR with some special schemes for enhancing the performance. We also describe the recent development of a high-speed con?guration of BOCDR (slope-assisted BOCDR), which offers a beyond-nominal-resolution detectability. The paper is summarized with some future prospects.
关键词： Brillouin scattering,optical fiber sensing,temperature sensing,distributed sensing,structural health monitoring,optical correlation-domain reflectometry,strain sensing,nonlinear optics
更新于2025-09-23 15:21:21
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Drying-induced soil shrinkage and desiccation cracking monitoring with distributed optical fiber sensing technique
摘要： Monitoring of drying-induced volume shrinkage and desiccation cracking in clayey soils is of great importance in geological and geotechnical engineering. Compared with conventional strain monitoring methods providing discrete measurements, the Brilliouin optical time domain reflectometer (BOTDR) technique enables continuous measurement of the distributed strain generated along optical fibers. In this study, a physical model test is conducted to investigate the feasibility of monitoring drying-induced soil shrinkage and desiccation cracking using BOTDR. Three optical fibers with different surface protections (thermoplastic polyester elastomer (TPEE) jacket, nylon jacket, and acrylate coating) are tested and compared. Experimental results validate that BOTDR is applicable for the direct strain monitoring of desiccation cracking soils. Monitored strain values are strongly influenced by water content, soil cracking, and fiber types. The strain measured by the optical fiber reaches only several micro strains when the soil is over-saturated, gradually increases with the decreasing water content and the increasing soil-fiber interfacial shear stresses, and drops rapidly after the occurrence of decoupling between fiber and soil resulting from the mature development of desiccation cracks. The optical fiber with acrylate coating is not suitable because of its fragility and the poor interfacial coupling with the soil. Optical fibers covered with TPEE jacket or nylon jacket are both applicable for soil strain monitoring, with the former one more sensitive to water content variations. The study is the first attempt to apply the BOTDR technique for the direct and continuous monitoring of drying-induced soil shrinkage and desiccation cracking process. It is expected bring new insights into the fundamental understanding of volumetric shrinkage and desiccation cracking in clayey soils.
关键词： Brilliouin optical time domain reflectometer (BOTDR),Desiccation crack,Volumetric shrinkage,Strain monitoring,Optical fiber sensing
更新于2025-09-23 15:21:01
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Helical optical fiber sensing configuration for hyper-elastic soft surgical manipulators
摘要： Soft surgical manipulator is a research hotspot, but the sensing problem of hyper-elastic deformation needs to be solved urgently. In order to solve this problem, a helical optical fiber sensing method is proposed for the manipulator of hyper-elastic soft material. A FBG(Fiber Bragg Grating) sensor is embedded in a helical shape in the soft manipulator. In theory, the helical fiber sensing model is established. The reflectance spectra of the FBG sensor was measured when the soft manipulator was compressed or bent. The relationship between the center wavelength offset and the compression amount, the center wavelength offset and the bending angle, respectively, was analyzed. The results show that the compression of the soft manipulator is approximately liner to the shift of the center wavelength of the FBG in the range of 0–18 mm, and the bending angle of the soft manipulator is non-linear to the shift of the center wavelength of the FBG sensor. The helical fiber grating sensor has good consistency in many measurement experiments, and the fluctuation range of the deviation index is -35%-25%. The main idea of the thesis is feasible and provide a method of the posture sensing of the soft surgery manipulator.
关键词： Hyper-elastic material,Optical fiber sensing,Soft manipulator,Helical structure
更新于2025-09-19 17:13:59
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Experimental Study on the Movement and Evolution of Overburden Strata Under Reamer-Pillar Coal Mining Based on Distributed Optical Fiber Monitoring
摘要： Focusing on the deterioration of the surface ecological environment caused by large-scale exploitation of the Jurassic coal field in northern Shaanxi, the three-dimensional similar material test model is made to simulate the extraction of shallow coal seam. Using Brillouin optical time-domain analysis (BOTDA) optical fiber distributed sensing technology, this paper studied the strain distribution rule and movement characteristics of strata under reamer-pillar mining, analyzed the stability of the remaining coal pillars in the mining area, and obtained the strain contour graph of strata through calculations. The research result shows that the deformation of coal pillars in a safety-critical state under reamer-pillar mining experiences three stages. The stratum deformation is distributed in the shape of a pyramid with the mining area as the center. On the basis of the strain distribution of strata, the settlement curve and subsidence curve of strata deformation are determined to obtain the rupture angle and angle of draw. After being compared with the measured data, the angle values are almost the same.
关键词： BOTDA,reamer-pillar mining,stratum movement,optical fiber sensing,shallow coal seam
更新于2025-09-19 17:13:59
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Distributed optical fiber sensing: Review and perspective
摘要： Over the past few decades, optical fibers have been widely deployed to implement various applications in high-speed long-distance telecommunication, optical imaging, ultrafast lasers, and optical sensors. Distributed optical fiber sensors characterized by spatially resolved measurements along a single continuous strand of optical fiber have undergone significant improvements in underlying technologies and application scenarios, representing the highest state of the art in optical sensing. This work is focused on a review of three types of distributed optical fiber sensors which are based on Rayleigh, Brillouin, and Raman scattering, and use various demodulation schemes, including optical time-domain reflectometry, optical frequency-domain reflectometry, and related schemes. Recent developments of various distributed optical fiber sensors to provide simultaneous measurements of multiple parameters are analyzed based on their sensing performance, revealing an inherent trade-off between performance parameters such as sensing range, spatial resolution, and sensing resolution. This review highlights the latest progress in distributed optical fiber sensors with an emphasis on energy applications such as energy infrastructure monitoring, power generation system monitoring, oil and gas pipeline monitoring, and geothermal process monitoring. This review aims to clarify challenges and limitations of distributed optical fiber sensors with the goal of providing a pathway to push the limits in distributed optical fiber sensing for practical applications.
关键词： energy applications,Brillouin scattering,Rayleigh scattering,Raman scattering,optical time-domain reflectometry,distributed optical fiber sensing,optical frequency-domain reflectometry
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Bipolar coding for phase-demodulated Φ-OTDR with coherent detection
摘要： The non-return-to-zero bipolar Golay code is successfully employed in phase-demodulated Φ-OTDR utilizing heterodyne detection. Compared with unipolar scenario, the superior performance is demonstrated in 10 km sensing experiment with doubled response bandwidth for perturbation, sub-meter spatial resolution and pico-strain resolution. This work paves the way for optical pulse coding based on bipolar sequences or matrix in Φ-OTDR.
关键词： Phase-sensitive optical time-domain reflectometry,Golay code,Optical fiber sensing
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - A Nonlinear Tuning Compensation Method for OFDR Systems Based on Polynomial Regression Algorithm
摘要： A nonlinear tuning compensation method for optical frequency domain reflection systems based on polynomial regression algorithm is proposed in this paper. Simulation results demonstrate that this method has greatly improved the spatial resolution of measurement.
关键词： Distributed optical fiber sensing,Optical frequency domain reflection,Polynomial regression algorithm,Nonlinear tuning compensation
更新于2025-09-16 10:30:52
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Research on high resolution fiber Bragg grating sensing technology based on high speed parallel sampling
摘要： The high resolution fiber Bragg sensing system based on high speed parallel sampling technology is proposed. According to the Rayleigh criterion, it is generally believed that the number of the measured data of the fiber grating reflection spectrum is limited to the resolution of the wavelength measurement device. So, in order to achieve high spectral resolution, high resolution wavelength measurement devices, at the same time, to achieve small variations of the transmission wavelength of the Fabry–Perot (FP) filter, the high bit digital-to-analog converter (DAC) was adopted to generates small step drive voltages, these will greatly increase the cost of the system. However, in this paper, the fiber Bragg sensing system with the low resolution FP filter and low bit DAC achieves the high resolution wavelength measurement by using the high speed parallel sampling. In addition, the resolution of wavelength in fiber grating sensing system is analyzed theoretically.
关键词： Parallel sampling technology,Wavelength resolution,Fiber Bragg grating,Optical fiber sensing
更新于2025-09-10 09:29:36
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Distributed Fiber Optical Technology for Damage Identification of Engineering Structure
摘要： To conduct optical fiber monitoring rock slide model test and optical fiber monitoring of steel concrete interface slip model test, the large tri-axial shear test of geotechnical engineering was used. First, the data of sliding distance and optical loss and their dynamic range were obtained. Second, the slide distance and fiber loss relation curve and the fitting equation were worked out. Finally, the typical applications of optical fiber sensing technology in Rock Engineering (high slope engineering, rock foundation of Dam Engineering) slope stability and geological disaster monitoring were put forward. The results showed that optical fiber sensing was very sensitive, and the loss value was 30 to 50dB. The dynamic range of rock slide monitoring fiber was 3 to 3.5mm, and the dynamic range of the interface slip monitoring fiber was 1.6mm. Thus, the sensing system can detect the sliding process of the interface between the concrete and the steel plate. It provides some reference for the sliding monitoring of the composite materials.
关键词： Optical fiber sensing technology,engineering structure damage,sliding distance-fiber loss
更新于2025-09-04 15:30:14