scholarly journals Fiber-optic vector acoustic receiver based on adaptive holographic interferometer

Laser Physics ◽  
2022 ◽  
Vol 32 (2) ◽  
pp. 025101
Author(s):  
R V Romashko ◽  
D V Storozhenko ◽  
M N Bezruk ◽  
D A Bobruyko ◽  
Y N Kulchin
Keyword(s):  
Acoustic Waves ◽  
Fiber Optic ◽  
Field Tests ◽  
Water Area ◽  
Acoustic Source ◽  
Acoustic Intensity ◽  
Holographic Interferometer ◽  
Intensity Vector ◽  
Fiber Optical ◽  
Acoustic Receiver

Abstract A mobile scalar–vector acoustic receiver is proposed, experimentally implemented and investigated. The key components of the receiver are (a) the six-channel fiber-optic coil-type sensor configured as to detect three projections of acoustic intensity vector, (b) the six-channel optical phase demodulator based on six-channel adaptive holographic interferometer configured with use of dynamic holograms multiplexed in a photorefractive crystal of cadmium telluride and (c) the signals recording ADC-based system combined with software package for data processing. Field tests of the developed receiver applied for obtaining scalar and vector parameters of acoustic waves generated by a stationary and moving acoustic source in open air and water area are carried out. Experimental results show perceptiveness of use of the fiber-optical adaptive interferometry system for bearing of weak acoustic sources in real conditions.

Laboratory and field tests of the active composite fence with integrated fiber optic modalmetric sensor and electromagnetic sensor

2016 ◽  
Author(s):  
Konrad Brewczyński ◽  
Marek Życzkowski ◽  
Mieczyslaw Szustakowski ◽  
Łukasz Olszewski ◽  
Piotr Markowski ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Field Tests ◽  
Electromagnetic Sensor ◽  
Active Composite

STABILIZATION OF THE REFERENCE SIGNAL PHASE OF THE FIBER OPTICAL DISTRIBUTION UHF SYSTEM

2021 ◽  
pp. 120-124
Author(s):  
S. A. Ostanin ◽  
M. D. Zhumadilov
Keyword(s):  
Wavelength Range ◽  
Distribution System ◽  
Fiber Optic ◽  
Reference Signal ◽  
Phase Delay ◽  
Original Design ◽  
Signal Phase ◽  
Fiber Optical ◽  
Reference Signals ◽  
Optical Distribution

The purpose and composition of the radio-photon components of the fiber-optic distribution system of reference signals of the decimeter wavelength range are described. The principle of the components of the fiber-optic distribution system of reference signals is described. The possibility of creating radio-photon components with improved technical characteristics in comparison with the closest foreign functional analogues has been proved. High technical characteristics are achieved by the original design and parametric compensation of the phase delay of the signal.

A variety of surface waves in ocean-bottom DAS records

2021 ◽  
Author(s):  
Zack Spica ◽  
Loïc Viens ◽  
Jorge Castillo Castellanos ◽  
Takeshi Akuhara ◽  
Kiwamu Nishida ◽  
...  
Keyword(s):  
Surface Wave ◽  
Acoustic Waves ◽  
Fiber Optic ◽  
Acoustic Noise ◽  
Seismic Exploration ◽  
Ocean Bottom ◽  
Wide Range ◽  
Ocean Layer ◽  
Noise Cross Correlation ◽  
Low Amplitude

<p>Distributed acoustic sensing (DAS) can transform existing telecommunication fiber-optic cables into arrays of thousands of sensors, enabling meter-scale recordings over tens of kilometers. Recently, DAS has demonstrated its utility for many seismological applications onshore. However, the use of offshore cables for seismic exploration and monitoring is still in its infancy.<br>In this work, we introduce some new results and observations obtained from a fiber-optic cable offshore the coast of Sanriku, Japan. In particular, we focus on surface wave retrieved from various signals and show that ocean-bottom DAS can be used to extract dispersion curves (DC) over a wide range of frequencies. We show that multi-mode DC can be easily extracted from ambient seismo-acoustic noise cross-correlation functions or F-K analysis. Moderate magnitude earthquakes also contain multiple surface-wave packets that are buried within their coda. Fully-coupled 3-D numerical simulations suggest that these low-amplitude signals originate from the continuous reverberations of the acoustic waves in the ocean layer. </p>

scholarly journals The Fiber Optic Link and Delay System at OVRO

1994 ◽  
Vol 140 ◽  
pp. 115-116
Author(s):  
Schubert F. Soares ◽  
Stephen Padin
Keyword(s):  
Fiber Optic ◽  
Composite Fiber ◽  
Delay System ◽  
System With Delay ◽  
Microwave System ◽  
Fiber Optical ◽  
And Performance ◽  
System Operating

AbstractThe design and performance details for a link, and a tracking delay system operating in the 0.5 to 4 GHz band are presented. This is a composite fiber optical and microwave system, with delay bits ranging from 512 to ns in binary steps.

scholarly journals Field validation of imaging an adjacent borehole using scattered P-waves

2020 ◽  
Vol 17 (5) ◽  
pp. 1272-1280
Author(s):  
Jian-Lin Ben ◽  
Wen-Xiao Qiao ◽  
Xiao-Hua Che ◽  
Xiao-Dong Ju ◽  
Jun-Qiang Lu ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Phased Array ◽  
Test Results ◽  
Field Validation ◽  
Geologic Structure ◽  
P Waves ◽  
Acoustic Reflection ◽  
Acoustic Receiver ◽  
Logging Tool ◽  
Array Receiver

Abstract Acoustic waves enter a rock formation from a borehole and are reflected or scattered upon encountering a geologic structure. Consequently, we obtain the structure location represented by the azimuth and distance from the borehole using the acoustic reflection or scattering. Downhole acoustic measurements with the azimuthal resolution are realized using an azimuthal acoustic receiver sonde composed of several arcuate phased array receivers. Eight sensors distributed evenly across the arcuate phased array receiver can record acoustic waves independently; this allows us to adopt the beamforming method. We use a supporting logging tool to conduct the downhole test in two adjacent fluid-filled boreholes, for validating the evaluation of the geologic structure using scattered P-waves. The test results show the multi-azimuth images of the target borehole and the azimuthal variation in scattering amplitudes. Thus, we obtain the precise location of the target borehole. Furthermore, the measured values of the target borehole are consistent with the actual values, indicating that we can accurately evaluate a near-borehole geologic structure with scattered P-waves.

scholarly journals Localization of Transient Events Threatening Pipeline Integrity by Fiber-Optic Distributed Acoustic Sensing

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3322 ◽  
Author(s):  
Maria-Teresa Hussels ◽  
Sebastian Chruscicki ◽  
Detlef Arndt ◽  
Swen Scheider ◽  
Jens Prager ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Fiber Optic ◽  
Optical Fiber Sensor ◽  
Pressure Waves ◽  
Fast Time ◽  
Acoustic Sensing ◽  
Damage Scenarios ◽  
Pressure Transducers ◽  
Transient Events ◽  
Distributed Acoustic Sensing

Pipe integrity is a central concern regarding technical safety, availability, and environmental compliance of industrial plants and pipelines. A condition monitoring system that detects and localizes threats in pipes prior to occurrence of actual structural failure, e.g., leakages, especially needs to target transient events such as impacts on the pipe wall or pressure waves travelling through the medium. In the present work, it is shown that fiber-optic distributed acoustic sensing (DAS) in conjunction with a suitable application geometry of the optical fiber sensor allows to track propagating acoustic waves in the pipeline wall on a fast time-scale. Therefore, short impacts on the pipe may be localized with high fidelity. Moreover, different acoustic modes are identified, and their respective group velocities are in good agreement with theoretical predications. In another set of experiments modeling realistic damage scenarios, we demonstrate that pressure waves following explosions of different gas mixtures in pipes can be observed. Velocities are verified by local piezoelectric pressure transducers. Due to the fully distributed nature of the fiber-optic sensing system, it is possible to record accelerated motions in detail. Therefore, in addition to detection and localization of threatening events for infrastructure monitoring, DAS may provide a powerful tool to study the development of gas explosions in pipes, e.g., investigation of deflagration-to-detonation-transitions (DDT).

Applicability of fiber optic sensors to the detection of surface acoustic waves on metals

1993 ◽  
Author(s):  
Derek J. Glennie ◽  
A. Tino Alavie ◽  
Kexing Liu ◽  
Raymond M. Measures
Keyword(s):  
Acoustic Waves ◽  
Fiber Optic ◽  
Surface Acoustic Waves ◽  
Fiber Optic Sensors

In Situ Sensing of Volatile Organic Compounds in Groundwater: First Field Tests of a Mid-Infrared Fiber-Optic Sensing System

2003 ◽  
Vol 57 (6) ◽  
pp. 607-613 ◽  
Author(s):  
H. Steiner ◽  
M. Jakusch ◽  
M. Kraft ◽  
M. Karlowatz ◽  
T. Baumann ◽  
...  
Keyword(s):  
Real World ◽  
Fiber Optic ◽  
Silver Halide ◽  
Field Tests ◽  
Reference Analysis ◽  
Mid Infrared ◽  
Sensor Head ◽  
Aquifer System ◽  
Volatile Organic

A prototype mid-infrared sensor system for the determination of volatile organic pollutants in groundwater was developed and tested under real-world conditions. The sensor comprises a portable Fourier transform infrared spectrometer, coupled to the sensor head via mid-infrared transparent silver halide fiber-optic cables. A 10 cm unclad middle section of the 6-m-long fiber is coated with ethylene propylene copolymer in order to enrich the analytes within the penetration depth of the evanescent field protruding from the fiber sensor head. A mixture of tetrachloroethylene, dichlorobenzene, diethyl phthalate, and xylene isomers at concentrations in the low ppm region was investigated qualitatively and quantitatively in an artificial aquifer system filled with Munich gravel. This simulated real-world site at a pilot scale enables in situ studies of the sensor response and spreading of the pollutants injected into the system with controlled groundwater flow. The sensor head was immersed into a monitoring well of the aquifer system at a distance of 1 m downstream of the sample inlet and at a depth of 30 cm. Within one hour, the analytes were clearly identified in the fingerprint region of the IR spectrum (1300 to 700 cm−1). The results have been validated by head-space gas chromatography, using samples collected during the field measurement. Five out of six analytes could be discriminated simultaneously; for two of the analytes the quantitative results are in agreement with the reference analysis.

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