Analyzing Distributed Vibrating Sensing Technologies in Optical Meshes

Hundreds of kilometers of optical fibers are installed for optical meshes (OMs) to transmit data over long distances. The visualization of these deployed optical fibers is a highlighted issue because the conventional procedure can only measure the optical losses. Thus, this paper presents distributed vibration sensing (DVS) estimation mechanisms to visualize the optical fiber behavior installed for OMs which is not possible by conventional measurements. The proposed technique will detect the power of light inside the optical fiber, as well as different physical parameters such as the phase of transmitted light inside the thread, the frequency of vibration, and optical losses. The applicability of optical frequency domain reflectometry (OFDR) and optical time-domain reflectometry (OTDR) DVS techniques are validated theoretically for various state detection procedures in optical fibers. The simulation model is investigated in terms of elapsed time, the spectrum of a light signal, frequency, and the impact of many external physical accidents with optical fibers.

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Damage detection in laminar thermoplastic composite materials by means of embedded optical fibers

Hemijska industrija ◽

10.2298/hemind0608176k ◽

2006 ◽

Vol 60 (7-8) ◽

pp. 176-179

Author(s):

Aleksandar Kojovic ◽

Irena Zivkovic ◽

Ljiljana Brajovic ◽

Dragan Mitrakovic ◽

Radoslav Aleksic

Keyword(s):

Composite Materials ◽

Optical Fiber ◽

Real Time ◽

Optical Fibers ◽

Impact Damage ◽

Experimental Testing ◽

Low Energy ◽

Thermoplastic Composite ◽

Woven Fabric ◽

The Impact

This paper investigates the possibility of applying optical fibers as sensors for investigating low energy impact damage in laminar thermoplastic composite materials, in real time. Impact toughness testing by a Charpy impact pendulum with different loads was conducted in order to determine the method for comparative measurement of the resulting damage in the material. For that purpose intensity-based optical fibers were built in to specimens of composite materials with Kevlar 129 (the DuPont registered trade-mark for poly(p-phenylene terephthalamide)) woven fabric as reinforcement and thermoplastic PVB (poly(vinyl butyral)) as the matrix. In some specimens part of the layers of Kevlar was replaced with metal mesh (50% or 33% of the layers). Experimental testing was conducted in order to observe and analyze the response of the material under multiple low-energy impacts. Light from the light-emitting diode (LED) was launched to the embedded optical fiber and was propagated to the phototransistor-based photo detector. During each impact, the signal level, which is proportional to the light intensity in the optical fiber, drops and then slowly recovers. The obtained signals were analyzed to determine the appropriate method for real time damage monitoring. The major part of the damage occurs during impact. The damage reflects as a local, temporary release of strain in the optical fiber and an increase of the signal level. The obtained results show that intensity-based optical fibers could be used for measuring the damage in laminar thermoplastic composite materials. The acquired optical fiber signals depend on the type of material, but the same set of rules (relatively different, depending on the type of material) could be specified. Using real time measurement of the signal during impact and appropriate analysis enables quantitative evaluation of the impact damage in the material. Existing methods in most cases use just the intensity of the signal before and after the impact, as the measure of damage. This method could be used to monitor the damage in real time, giving warnings before fatal damage occurs.

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Comparative Experimental Study of a High-Temperature Raman-Based Distributed Optical Fiber Sensor with Different Special Fibers

Sensors ◽

10.3390/s19030574 ◽

2019 ◽

Vol 19 (3) ◽

pp. 574 ◽

Cited By ~ 10

Author(s):

Ismail Laarossi ◽

María Quintela-Incera ◽

José López-Higuera

Keyword(s):

Experimental Study ◽

High Temperature ◽

Optical Fiber ◽

Optical Fibers ◽

Optical Fiber Sensor ◽

Time Domain Reflectometry ◽

Fiber Sensor ◽

Mechanical Resistance ◽

Distributed Optical Fiber Sensor ◽

Distributed Optical Fiber

An experimental study of a high temperature distributed optical fiber sensor based on Raman Optical-Time-Domain-Reflectometry (ROTDR) (up to 450 °C) and optical fibers with different coatings (polyimide/carbon, copper, aluminum and gold) is presented. Analysis of the distributed temperature sensor (DTS) measurements determined the most appropriate optical fiber to be used in high temperature industrial environment over long periods of time. To demonstrate the feasibility of this DTS for an industrial application, an optical cable was designed with the appropriate optical fiber and it was hermetically sealed to provide the required mechanical resistance and isolate the fiber from environmental degradations. This cable was used to measure temperature up to 360 °C of an industrial furnace during 7 days.

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Wavelength-Scanning Distributed Acoustic Sensing for Structural Monitoring and Seismic Applications

Proceedings ◽

10.3390/proceedings2019015030 ◽

2019 ◽

Vol 15 (1) ◽

pp. 30 ◽

Cited By ~ 1

Author(s):

Sascha Liehr ◽

Sven Münzenberger ◽

Katerina Krebber

Keyword(s):

Optical Fibers ◽

Ground Deformation ◽

Measurement Data ◽

Spectral Shift ◽

Time Domain Reflectometry ◽

Vibration Monitoring ◽

Surface Wave Propagation ◽

Wavelength Scanning ◽

Vibration Sensing ◽

Optical Time

We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks (ANNs) are used for fast and high-resolution strain computation from raw measurement data. The applicability of the method is demonstrated for vibration monitoring of a reinforced concrete bridge. We demonstrate another application example for quasi-static and dynamic measurement of ground deformation and surface wave propagation along a dark fiber in a telecommunication cable.

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Monitoring Axial Strain in Synthetic Fiber Mooring Ropes Using Polymeric Optical Fibers

Volume 1: Offshore Technology; Ocean Space Utilization ◽

10.1115/omae2003-37402 ◽

2003 ◽

Author(s):

D. Barton Smith ◽

Jerry G. Williams

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Structural Integrity ◽

Axial Strain ◽

Time Domain Reflectometry ◽

Synthetic Fiber ◽

Load Path ◽

Integrity Test ◽

Reliable Technique ◽

Polymeric Optical Fibers

Synthetic fiber ropes constructed of polyester are providing an important new technology for mooring deep-water drilling and production platforms. Considerable effort is being directed toward advancing and qualifying this enabling and cost-effective technology. To date, synthetic fiber mooring ropes have been successfully deployed in Brazil and they have seen limited service in the Gulf of Mexico. Synthetic fiber mooring ropes have high strength-to-weight ratios and possess adequate stiffness, but they are much more susceptible to damage than their steel counterparts. Future safe deployment of synthetic fiber mooring ropes would be significantly enhanced if a reliable technique were available to monitor the performance of the ropes in service and thus provide an early warning of the loss of structural integrity. Test data in the open literature indicates that the strain in the rope at failure is essentially a constant independent of load path or history. Measurement of the accumulated strain in the rope should thus provide a reliable benchmark with which to estimate the remaining life and establish criteria for rope recertification or retirement. This paper discusses the results of research and development activities aimed at developing a reliable, robust method for monitoring strain in braided and twisted strand Synthetic Fiber Mooring Ropes [1]. The strain transducer is a polymeric optical fiber, integrated into the mooring rope and interrogated with Optical Time-Domain Reflectometry (OTDR) to measure changes in its length as the optical fiber and rope are stressed. The method provides a direct measurement of large axial strains. Strains measured in polymeric optical fibers exhibit good one-to-one correlation with applied strains within the test range studied (10% or less, typically). The integrated polymeric optical fiber has been shown to withstand large numbers of repeated cycles to high strains without failure and to accurately track the hysteresis exhibited by polyester rope. Results are reported for tests conducted with polymeric optical fibers integrated into typical mooring rope elements.

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Исследование оптических свойств многомодового кварцевого оптического волокна с отражающей оболочкой из фторированного термопластичного полимера

Журнал технической физики ◽

10.21883/os.2019.09.48206.107-19 ◽

2019 ◽

Vol 127 (9) ◽

pp. 477

Author(s):

А.А. Маковецкий ◽

А.А. Замятин ◽

Д.В. Ряховский

Keyword(s):

Optical Properties ◽

Optical Fiber ◽

Optical Fibers ◽

Scattered Radiation ◽

Fiber Length ◽

Numerical Aperture ◽

Optical Losses ◽

Laser Medicine ◽

Propagation Of Light ◽

Absorption Of Light

Optical properties silica - polymeric optical fiber with a core with a diameter of 430 microns and the reflecting cover 70 microns thick from thermoplastic copolymer of a tetraftoretilen with ethylene (Tefzel brand) are experimentally investigated. The polymeric cover is applied on silica fiber with applicator from polimer melt directly on drowing tower. Optical losses of the fiber, a numerical aperture and its dependence on fiber length are measured. It is established that at propagation of light in fiber its noticeable scattering is observed. It is connected with crystallinity of polymeric cover. Distribution of intensity of scattered radiation along an axis of fiber and an indicatrix of dispersion of radiation by a coating are measured. Relative deposits of dispersion and absorption of light in a cover at the general optical losses of fiber are estimated. The possibility of use of optical fibers of this structure in laser medicine is considered.

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Engineering nanoparticle features to tune Rayleigh scattering in nanoparticles-doped optical fibers

Scientific Reports ◽

10.1038/s41598-021-88572-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Victor Fuertes ◽

Nicolas Grégoire ◽

Philippe Labranche ◽

Stéphane Gagnon ◽

Ruohui Wang ◽

...

Keyword(s):

Optical Fiber ◽

Long Range ◽

Optical Fibers ◽

Rayleigh Scattering ◽

Distributed Sensing ◽

Optical Losses ◽

Sensing Applications ◽

Fiber Fabrication ◽

Silica Fibers ◽

Potential Applications

AbstractRayleigh scattering enhanced nanoparticles-doped optical fibers are highly promising for distributed sensing applications, however, the high optical losses induced by that scattering enhancement restrict considerably their sensing distance to few meters. Fabrication of long-range distributed optical fiber sensors based on this technology remains a major challenge in optical fiber community. In this work, it is reported the fabrication of low-loss Ca-based nanoparticles doped silica fibers with tunable Rayleigh scattering for long-range distributed sensing. This is enabled by tailoring nanoparticle features such as particle distribution size, morphology and density in the core of optical fibers through preform and fiber fabrication process. Consequently, fibers with tunable enhanced backscattering in the range 25.9–44.9 dB, with respect to a SMF-28 fiber, are attained along with the lowest two-way optical losses, 0.1–8.7 dB/m, reported so far for Rayleigh scattering enhanced nanoparticles-doped optical fibers. Therefore, the suitability of Ca-based nanoparticles-doped optical fibers for distributed sensing over longer distances, from 5 m to more than 200 m, becomes possible. This study opens a new path for future works in the field of distributed sensing, since these findings may be applied to other nanoparticles-doped optical fibers, allowing the tailoring of nanoparticle properties, which broadens future potential applications of this technology.

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Towards Distributed Measurements of Electric Fields Using Optical Fibers: Proposal and Proof-Of-Concept Experiment

Sensors ◽

10.3390/s20164461 ◽

2020 ◽

Vol 20 (16) ◽

pp. 4461 ◽

Cited By ~ 1

Author(s):

Regina Magalhães ◽

João Pereira ◽

Oleksandr Tarasenko ◽

Sonia Martin-Lopez ◽

Miguel González-Herráez ◽

...

Keyword(s):

Optical Fiber ◽

Electric Fields ◽

Optical Fibers ◽

Electromagnetic Interference ◽

Time Domain Reflectometry ◽

Second Order ◽

Third Order ◽

Electrical Fields ◽

Silica Fibers ◽

Highly Sensitive

Nowadays there is an increasing demand for the cost-effective monitoring of potential threats to the integrity of high-voltage networks and electric power infrastructures. Optical fiber sensors are a particularly interesting solution for applications in these environments, due to their low cost and positive intrinsic features, including small size and weight, dielectric properties, and invulnerability to electromagnetic interference (EMI). However, due precisely to their intrinsic EMI-immune nature, the development of a distributed optical fiber sensing solution for the detection of partial discharges and external electrical fields is in principle very challenging. Here, we propose a method to exploit the third-order and second-order nonlinear effects in silica fibers, as a means to achieve highly sensitive distributed measurements of external electrical fields in real time. By monitoring the electric-field-induced variations in the refractive index using a highly sensitive Rayleigh-based CP-φOTDR scheme, we demonstrate the distributed detection of Kerr and Pockels electro-optic effects, and how those can assign a new sensing dimension to optical fibers, transducing external electric fields into visible minute disturbances in the guided light. The proposed sensing configuration, electro-optical time domain reflectometry, is validated both theoretically and experimentally, showing experimental second-order and third-order nonlinear coefficients, respectively, of χ(2) ~ 0.27 × 10−12 m/V and χ(3) ~ 2.5 × 10−22 m2/V2 for silica fibers.

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The influence of concentration of Nd-Fe-B powder in composite coating of optical fiber to the sensibility to external magnetic field

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb0501103r ◽

2005 ◽

Vol 41 (1) ◽

pp. 103-111 ◽

Cited By ~ 1

Author(s):

Vesna Radojevic ◽

T. Serbez ◽

R. Aleksic ◽

D. Nedeljkovic ◽

Lj. Brajovic

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Optical Fiber ◽

Composite Coating ◽

Optical Fibers ◽

Optical Fiber Sensor ◽

Light Signal ◽

Magnetic Composite ◽

Sensor Element ◽

Optical Propagation

Multi-mode optical fiber with magnetic composite coating was investigated as an optical fiber sensor element (OFMSE) for magnetic field sensing The composite coating was formed with dispersions of permanent magnet powder of Nd-Fe-B in poly (ethylene-co-vinyl acetate)-EVA solutions in toluene. The influence of the applied external magnetic field on the change of intensity of the light signal propagate trough developed optical fibers sensor element was investigated. In this paper the influence of the content of magnetic powder in the composite coating on the optical propagation characteristics of optical fiber were particularly investigated.

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Testing of a Polarimetric Current Sensor in the Frequency Domain

Sensors ◽

10.3390/s21093008 ◽

2021 ◽

Vol 21 (9) ◽

pp. 3008

Author(s):

Sławomir Andrzej Torbus ◽

Jacek Andrzej Michalski

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Measurement Errors ◽

Scientific Research ◽

Single Mode ◽

Market Potential ◽

Current Sensor ◽

Industrial Property ◽

Measuring Coil ◽

The Impact

This paper proposes an original model of a polarimetric current sensor, in which the measuring coil was made of a single mode telecommunication optical fiber ITU-T G.652, G.653, G.655, and G.657. This sensor was subjected to the commercialization process, which was carried out by a company combining the functionality of a technology transfer center with the capabilities of the Startit Fund Sp. z o.o. The published results included the analysis of the implementation readiness, the analysis of the market potential, the valuation of the industrial property rights of the invention and indicated further directions of scientific research on the sensor, which include the frequency analysis of measurement signals. This prompted the conduct of relevant scientific research. In this paper, the idea of measurement of current using polarimetric current sensor with optical fiber coil has been briefly characterized. It shows the definition and basic properties of the Discrete Fourier Transform (DFT). It discusses the technique of determining the value of each harmonic of signal at the input and output of polarimetric current sensor. The value of measurement errors and total harmonic distortion (THD) have been calculated. The general conclusions for disturbances in the processing realized in polarimetric current sensor have been formulated. In addition, the impact of the molar concentration of the dopant GeO2 in the core of the single mode telecommunication optical fibers and the impact of the number of turns of the measuring coil on the distortion accompanying the process of processing have been determined. Therefore, it can be concluded that the key result obtained during the research is the confirmation of the fact that single mode telecommunication optical fibers can be used to build the measuring coil of a polarimetric sensor used for measuring alternating currents. This means that the considered sensor, when measuring this type of currents, does not introduce additional distortions and distortions of their waveforms.

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Optical Strain Measurement with Step-Index Polymer Optical Fiber Based on the Phase Measurement of an Intensity-Modulated Signal

Sensors ◽

10.3390/s18072319 ◽

2018 ◽

Vol 18 (7) ◽

pp. 2319 ◽

Cited By ~ 5

Author(s):

Thomas Becker ◽

Olaf Ziemann ◽

Rainer Engelbrecht ◽

Bernhard Schmauss

Keyword(s):

Refractive Index ◽

Optical Fiber ◽

Optical Fibers ◽

Phase Measurement ◽

Polymer Optical Fiber ◽

Step Index ◽

Intensity Modulated ◽

Optical Strain ◽

The Impact ◽

Multi Mode

Polymer optical fibers (POFs) have been proposed for optical strain sensors due to their large elastic strain range compared to glass optical fibers (GOFs). The phase response of a single-mode polymer optical fiber (SM-POF) is well-known in the literature, and depends on the physical deformation of the fiber as well as the impact on the refractive index of the core. In this paper, we investigate the impact of strain on a step-index polymer optical fiber (SI-POF). In particular, we discuss the responsivity of an optical strain sensor which is based on the phase measurement of an intensity-modulated signal. In comparison to the phase response of an SM-POF, we must take additional influences into account. Firstly, the SI-POF is a multi-mode fiber (MMF). Consequently, we not only consider the strain dependence of the refractive index, but also its dependency on the propagation angle θz. Second, we investigate the phase of an intensity-modulated signal. The development of this modulation phase along the fiber is influenced by modal dispersion, scattering, and attenuation. The modulation phase therefore has no linear dependency on the length of the fiber, even in the unstrained state. For the proper consideration of these effects, we rely on a novel model for step-index multi-mode fibers (SI-MMFs). We expand the model to consider the strain-induced effects, simulate the strain responsivity of the sensor, and compare it to experimental results. This led to the conclusion that the scattering behavior of a SI-POF is strain-dependent, which was further proven by measuring the far field at the end of a SI-POF under different strain conditions.

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