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Conference on sensors for Extreme Harsh Environments

作者： Zhu, Hui Pan, Chao Sun, Xiaohan Southeast Univ Dept Elect Engn Natl Res Ctr Opt Sensing Commun Integrated Networ Nanjing 210096 Jiangsu Peoples R China

ISBN: (纸本)9781628410501

In this paper, the compensating scheme for the large noise induced by rainfall in the distributed optical-fiber vibration sensor engineering system (DFVSES) is proposed and demonstrated. DFVSES with rainfall compensation is made up of two subsystems using a common optical source and same optical circuit. Analyzing spectrum of the output signals under rainfall condition, and comparing the amplitude of the output signal for the sensing subsystem and the amplitude calculated from the amplitude of the output signal for the reference subsystem, the vibration can be got in the harsh climatic environments. We set up the experimental system, and the results show DFVSES with the scheme can effectively work under rainfall condition.

关键词： distributed optical-fiber sensor engineering system harsh climatic environment rainfall compensation

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62 km COTDR for Long-Distance distributed Temperature Sensing with a Noise-Reduction Signal Processing Method

62 km COTDR for Long-Distance Distributed Temperature Sensin...

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Asia Communications and Photonics Conference (ACP)

作者： Song, Muping Wu, Ying Zhu, Weiji Zhuang, Shouwang Wang, Yixuan Zhejiang Univ Coll Informat Sci & Elect Engn Hangzhou Zhejiang Peoples R China

A coherent optical time-domain reflectometry (COTDR) for 62km long-distance distributed temperature sensing is demonstrated experimentally. A noise-reduction signal processing method is adopted to improve the detectin... 详细信息

ISBN: (纸本)9781538661581

关键词： distributed optical-fiber sensor long distance temperature sensing

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Vibration Pattern Recognition and Classification in OTDR Based distributed optical-fiber Vibration Sensing System

Vibration Pattern Recognition and Classification in OTDR Bas...

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Conference on Smart sensor Phenomena, Technology, Networks, and Systems Integration

作者： Zhu, Hui Pan, Chao Sun, Xiaohan Southeast Univ Natl Res Ctr Opt Sensing Commun Integrated Networ Dept Elect Engn Nanjing 210096 Jiangsu Peoples R China

ISBN: (纸本)9780819499882

In this paper we propose and demonstrate the scheme of vibration pattern recognition and classification in the OTDR based distributed optical-fiber vibration sensing system. We set up the engineering system with signal processing PC for perimeter security in some high-tech park in Nanjing. Three types of disturbing actions, including climbing up and kicking at the wall by a person, and watering on the sensing optical fiber cable same as the rain falling on, are implemented. By using level crossing rate (LCR), we can obtain their individual pattern features, so that the eigenvalue database for three disturbing actions can be built in the system. By comparing three types of vibrations, the differences among these can be given out. The results show three vibration patterns can be recognized and classified effectively.

关键词： distributed optical-fiber sensor OTDR vibration waveform reproduction location pattern recognition

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Vibration Waveform Reproduction and Location of OTDR Based distributed optical-fiber Vibration Sensing System

Vibration Waveform Reproduction and Location of OTDR Based D...

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Conference on Quantum Sensing and Nanophotonic Devices XI

作者： Zhu, Hui Pan, Chao Sun, Xiaohan Southeast Univ Natl Res Ctr Opt Sensing Commun Integrated Networ Nanjing 210096 Jiangsu Peoples R China

ISBN: (纸本)9780819499066

In this paper, the scheme for both reproducing vibration waveform and locating disturbed places in the OTDR based distributed optical fiber vibration sensing systems is proposed and demonstrated. Based on the sampling law, the vibration waveform is reproduced from the detecting pulses including original sensing signals by denoising selectively, adjusting bias voltage and band-pass filtering. The vibrations at the frequencies of 500Hz and 1000Hz have been experimentally located and reproduced, respectively, and the highest frequency of 1 kHz for reproducing vibration waveform is realized at the repeat frequency of 2 kHz for the laser.

关键词： distributed optical-fiber sensor OTDR vibration waveform reproduction location

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Stationary Wavelet Transform Method for distributed Detection of Damage by fiber-Optic sensors

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JOURNAL OF ENGINEERING MECHANICS 2014年第4期140卷 04013004-04013004页

作者： Feng, Xin Zhang, Xiaotan Sun, Changsen Motamedi, Mohammadhosein Ansari, Farhad Dalian Univ Technol Fac Infrastruct Engn Dalian 116023 Peoples R China Univ Illinois Dept Civil & Mat Engn Smart Sensors & NDT Lab Chicago IL 60607 USA Dalian Univ Technol Sch Phys & Optoelect Engn Dalian 116023 Peoples R China

Brillouin scattering-based fiber-optic sensors have been used in a number of applications, including monitoring of pipelines and well-casing damage in the oil and gas industry. The major attribute of these sensors is their capability for distributed sensing of strains along large sections of structures. For these reasons, Brillouin-based fiber-optic sensors have great potential for civil structural applications, such as in bridges. This study reports the investigation of the Brillouin optical time-domain reflectometer for assessing damage in structural members. The primary advantage in using the Brillouin optical time-domain reflectometer is the single-fiber installation and multidamage-detection capability for the entire structure. The challenge in using a Brillouin optical time-domain reflectometer for detection of localized damage is to overcome the effects of system noise and Brillouin frequency-peak shift distortions. The compound effects of noise and frequency-peak distortions result in dispersion of the localized strains and concealment of crack locations. A signal-processing approach based on the multiresolution analysis (MRA) of the distributed strain data by using the stationary wavelet-transform (SWT) method is introduced in this study. This approach was employed to enhance data quality and to extract the damage-related features from the distributed strain data. The process involved decomposition of the strain data and extraction of the approximate and detailed coefficients of the signal. The MRA of the data involved further transformation of the approximate coefficients to extract the crack features. Evaluation of the method was accomplished by using signal-processing methodology for detecting the damage locations in a 15-m-long beam with simulated damage during four-point bending experiments. By using the wavelet-transform approach, it was possible to detect the location of the simulated damage sections with joint opening displacements larger than 50 mm

关键词： distributed optical-fiber sensor Brillouin optical time-domain reflectometry (BOTDR) Damage detection Structural health monitoring Crack detection Stationary wavelet transform Multiresolution analysis

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Large electric current real-time control system based on wavelength division multiplexing optical fiber network

Large electric current real-time control system based on wav...

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Conference on Advanced sensor Systems and Applications

作者： Wan, X Gao, YQ Yu, SL Nanchang Inst Aeronaut Technol Dept Measuring & Control Engn Nanchang 330034 Peoples R China

ISBN: (纸本)0819447099

In the testing and control of electricity system, Magnetism-photo optical fiber electricity sensor modules based on Faraday Effect of the main electricity wire can be made. We can play these sensor modules at the spots where the, electricity need to be tested and controlled real-timely and make use of the Wavelength Division Multiplexing (WDM) technique of optical fiber network to transmit the real time data from all spots to the central computer, so the system of distributed optical fiber electricity current supervision and control is constructed.

关键词： wavelength division multiplex distributed optical-fiber sensor Faraday effect

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High spatial resolution soliton DOFS for smart structures

High spatial resolution soliton DOFS for smart structures

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SPIE Conference on Mathematics and Control in Smart Structures

作者： Song, MP Tang, WZ Zhou, W Zhejiang Univ Dept Informat & Elect Engn Hangzhou 310027 Peoples R China

ISBN: (纸本)0819427675

From the advantage and defect of current distributed optical-fiber sensor(DOFS) schemes, It could be seen that most of schemes except distributed anti-Stokes Ratio Termometry(DART) are only possible in experiment, but unpractical. But DART is not able to be used on small and fine things especially for smart structures, because of its poor spatial resolution. As we all know that the relaxation time of Raman scattering is in the femtosecond range, and a optical pulse with width >1ps will not receive gain reducing, so the potential spatial resolution of DART can be smaller than 0.1m, even 1mm(for a pulse with width <10ps). Considering these, we firstly propose a novel scheme of DOFS based on spontaneons Raman back-scatering and the effect of high-order soliton, which uses Time-correlated Single Photon Counting(TCPC) as detector. The first-order and high-order solitons' effect in the system are theoretically investigated, and it is found that it is able to improve the spatial resolution observably by using high-order soliton in relatively short sensing distance(<1km). In the end, the possibility and difficulties of realizing the system based on present-day level of devices are considered.

关键词： distributed optical-fiber sensor soliton spatial resolution back-scattering light smart structures

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