Distributed Fiber-Optic Vibration Sensing Based on Phase Extraction From Optical Reflectometry

Fan, Xinyu; Yang, Guangyao; Wang, Shuai; Liu, Qingwen; He, Zuyuan

doi:10.1109/jlt.2016.2604859

Cited by 71 publications

(24 citation statements)

References 31 publications

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“…Coherent optical time domain reflectometry (COTDR) is an intriguing technique for characterization and fault location in optical fibre transmission systems 41,42 as well as distributed fibre-optic dynamic strain sensing aiming to structural health monitoring 43,44 . In coherent OTDR system, the lightwave from a narrow-linewidth laser source is divided into two paths: the lightwave in the first path is temporally modulated into a pulse with a central frequency shift fs and then launched into one-end of long fibre while the lightwave in the second path remains cw as the local reference.…”

Section: Laser Phase Noise In Cotdr Systemmentioning

confidence: 99%

“…Coherent optical time domain reflectometry (COTDR) is a ubiquitous technique that typically captures the beating notes of a cw light source and its pulse-modulated signal from Rayleigh scattering along an optical fibre for a time-offlight measurement of position-resolved response from external disturbance. Either intensity 58 or phase43,50 interrogation based on COTDR could be implemented to achieve a distributed acoustic sensing.…”

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confidence: 99%

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Unveiling delay-time-resolved phase noise statistics of narrow-linewidth laser via coherent optical time domain reflectometry

2020

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Laser with high spectral purity plays a crucial role in high-precision optical metrology and coherent communication. Thanks to the rapid development of laser frequency stabilization, the laser phase noise can be remarkably compensated, allowing its ultra-narrow linewidth subject to mostly quantum limit. Nevertheless, the accurate characterization of phase noise dynamics and its intrinsic linewidth of a highly coherent laser remains ambiguous and challenging. Here, we present an approach capable of revealing delay-time-resolved phase noise dynamics of a coherent laser based on coherent optical time domain reflectometry (COTDR), in which distributed Rayleigh scattering along a delay fibre essentially allows a timeof-flight mapping of a heterodyne beating signal associated with delay-timedependent phase information from a single laser source. Ultimately, this novel technique facilitates a precise measurement of ultra-narrow laser linewidth by exploiting its delay-time-resolved phase jitter statistics, confirmed with the analytical modelling and numerical simulations. Correspondence should be addressed to L. Z. ( * email: opticaliang@gmail.com ) or to X. B. ( § email: xbao@uottawa.ca )

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Section: Laser Phase Noise In Cotdr Systemmentioning

confidence: 99%

mentioning

confidence: 99%

Unveiling delay-time-resolved phase noise statistics of narrow-linewidth laser via coherent optical time domain reflectometry

2020

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“…As one typical distributed optical fiber vibration sensing system, a phase-sensitive optical time domain reflectometer (Φ-OTDR) can achieve simultaneously multi-point vibration detection and location. Because of the benefits of its high sensitivity, good spatial resolution and long detecting distance [4,5], Φ-OTDR has broad application prospects in long-distance oil and gas pipelines [6], border security intrusion detection and smart grids [7,8]. The current research hotspot of Φ-OTDR is the improvement of its sensing performance, such as a sensing distance up to even hundreds of kilometers [9,10], and a spatial resolution of a sub-meter magnitude [11], which leads to a huge amount of sensing data and a growing demand for computation resources.…”

Section: Introductionmentioning

confidence: 99%

Co-Processing Parallel Computation for Distributed Optical Fiber Vibration Sensing

Wang

Jin

et al. 2020

Applied Sciences

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Rapid data processing is crucial for distributed optical fiber vibration sensing systems based on a phase-sensitive optical time domain reflectometer (Φ-OTDR) due to the huge amount of continuously refreshed sensing data. The vibration sensing principle is analyzed to study the data flow of Rayleigh backscattered light among the different processing units. A field-programmable gate array (FPGA) is first chosen to synchronously implement pulse modulation, data acquisition and transmission in parallel. Due to the parallelism characteristics of numerous independent algorithm kernels, graphics processing units (GPU) can be used to execute the same computation instruction by the allocation of multiple threads. As a conventional data processing method for the sensing system, a differential accumulation algorithm using co-processing parallel computation is verified with a time of 1.6 μs spent of the GPU, which is 21,250 times faster than a central processing unit (CPU) for a 2020 m length of optical fiber. Moreover, the cooperation processes of the CPU and GPU are realized for the spectrum analysis, which could shorten substantially the time of fast Fourier transform analysis processing. The combination of FPGA, CPU and GPU can largely enhance the capacity of data acquisition and processing, and improve the real-time performance of distributed optical fiber vibration sensing systems.

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“…X. Fan et al have demodulated the phase information successfully by Hilbert transform, and deeply studied the noise of phase [18][19]. F. Pang et al have obtained the spatial distribution characteristic of the statistical phase in the coherent Φ-OTDR system when the phase demodulation is used to resolve the fading discrimination [20].…”

Section: Introductionmentioning

confidence: 99%

Quantitative characteristic of phase signal with changed pulse in the coherent PHI-OTDR system

Zhong¹,

Zhang²

2020

Preprint

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In the coherent -OTDR system, the phase signal is retrieved based on the reference point and the observation point which are off and closer to the two sides of step of the phase change. In the experiment, the optical pulse with the changed peak power, width or shape is injected into the fiber for interrogating the change of the quantitative characteristic of the measured phase signal. When the pulse width is fixed at 200 ns and its peak power is adjusted from 14 dBm to -23 dBm, the amplitude is slightly increased from 17.3575 rad to 17.4411 rad as long as the Rayleigh backscattering signal can be found in the electrical signal. Changing the pulse width from 260 ns to 80 ns when the peak power is fixed at 14 dBm, the maximum amplitude and the minimum amplitude of the measured phase signal are 17.4625 rad to 17.4509 rad, respectively. When the arbitrary shape of the optical pulse generated from the MZI structure with a changed delay fiber from 3 m to 6 m, the amplitude varies from 17.4558 rad to 17.4819 rad. For every measurement, the change of frequency is also small. And the small value of standard deviation supports the accuracy of the measurement. All the measurements show that the changed pulse nearly has no impact on the quantitative characteristic of the measured phase signal in the coherent -OTDR system.

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Distributed Fiber-Optic Vibration Sensing Based on Phase Extraction From Optical Reflectometry

Cited by 71 publications

References 31 publications

Unveiling delay-time-resolved phase noise statistics of narrow-linewidth laser via coherent optical time domain reflectometry

Unveiling delay-time-resolved phase noise statistics of narrow-linewidth laser via coherent optical time domain reflectometry

Co-Processing Parallel Computation for Distributed Optical Fiber Vibration Sensing

Quantitative characteristic of phase signal with changed pulse in the coherent PHI-OTDR system

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