scholarly journals A Brief Review of Specialty Optical Fibers for Brillouin-Scattering-Based Distributed Sensors

2018 ◽  
Vol 8 (10) ◽  
pp. 1996 ◽  
Author(s):  
Peter Dragic ◽  
John Ballato
Keyword(s):  
Optical Fiber ◽  
Silicate Glass ◽  
Optical Fibers ◽  
Brillouin Scattering ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Fiber Design ◽  
New Thinking ◽  
Sensing Application ◽  
Brillouin Gain

Specialty optical fibers employed in Brillouin-based distributed sensors are briefly reviewed. The optical and acoustic waveguide properties of silicate glass optical fiber first are examined with the goal of constructing a designer Brillouin gain spectrum. Next, materials and their effects on the relevant Brillouin scattering properties are discussed. Finally, optical fiber configurations are reviewed, with attention paid to fibers for discriminative or other enhanced sensing configurations. The goal of this brief review is to reinforce the importance of fiber design to distributed sensor systems, generally, and to inspire new thinking in the use of fibers for this sensing application.

Pipeline Geohazard Risk Monitoring With Optical Fiber Distributed Sensors: Experience With Andean and Arctic Routes

2018 ◽  
Author(s):  
Fabien Ravet ◽  
Fabien Briffod ◽  
Sanghoon Chin ◽  
Etienne Rochat ◽  
Jean-Grégoire Martinez
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Brillouin Scattering ◽  
Weather Conditions ◽  
Spatial Location ◽  
Deformation Monitoring ◽  
Distributed Sensors ◽  
The Andes ◽  
Risk Monitoring ◽  
Geohazard Risk

Many pipelines are built in regions affected by harsh environmental conditions where changes in soil texture between winter and summer increase the likelihood of hazards. Pipeline routes also cross mountains that are characterized by steep slopes and unstable soils as in the Andes and along the coastal range of Brazil. In other cases, these pipelines are laid in remote areas with significant seismic activity or exposure to permafrost. Depending on weather conditions and location, visual inspection is difficult or even impossible and therefore remote sensing solutions for pipes offer significant advantages over conventional inspection techniques. Optical fibers can help solve these challenges. Optical fiber based geotechnical and structural monitoring use distributed measurement of strain and temperature thanks to the sensitivity of Brillouin scattering to mechanical and thermal effects. The analysis of scattering combined with a time domain technique allows the measurement of strain and temperature profiles. Temperature measurement is carried out to monitor soil erosion or dune migration through event quantification and spatial location. Direct measurement of strain in the soil also improves the detection of environmental hazards. As an example, the technology can pinpoint the early signs of landslides. In some cases, actual pipe deformation must be monitored such as in the case of an active tectonic fault crossing. Pipe deformation monitoring operation is achieved by the measurement of distributed strain along fiber sensors attached to the structure. This paper comprehensively reviews over 15 years of continuous development of pipeline geohazard risk monitoring with optical fiber distributed sensors from technology qualification and validation to its implementation in real cases as well as its successful continuous operation. Case studies presented include pipeline monitoring in Arctic and Siberian environment as well as in the Andes which illustrate how the technology is used and demonstrate proof of early detection and location of geohazard events such as erosion, landslide, settlement and pipe deformation.

scholarly journals Fast Measurement of Brillouin Frequency Shift in Optical Fiber Based on a Novel Feedforward Neural Network

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 474
Author(s):  
Fen Xiao ◽  
Mingxing Lv ◽  
Xinwan Li
Keyword(s):  
Neural Network ◽  
Optical Fiber ◽  
Frequency Shift ◽  
Brillouin Scattering ◽  
Principal Component ◽  
Feedforward Neural Network ◽  
Gain Spectrum ◽  
Fiber Sensors ◽  
Brillouin Gain ◽  
Distributed Optical Fiber

Brillouin scattering-based distributed optical fiber sensors have been successfully employed in various applications in recent decades, because of benefits such as small size, light weight, electromagnetic immunity, and continuous monitoring of temperature and strain. However, the data processing requirements for the Brillouin Gain Spectrum (BGS) restrict further improvement of monitoring performance and limit the application of real-time measurements. Studies using Feedforward Neural Network (FNN) to measure Brillouin Frequency Shift (BFS) have been performed in recent years to validate the possibility of improving measurement performance. In this work, a novel FNN that is 3 times faster than previous FNNs is proposed to improve BFS measurement performance. More specifically, after the original Brillouin Gain Spectrum (BGS) is preprocessed by Principal Component Analysis (PCA), the data are fed into the Feedforward Neural Network (FNN) to predict BFS.

scholarly journals Truly Distributed Optical Fiber Sensors for Structural Health Monitoring: From the Telecommunication Optical Fiber Drawling Tower to Water Leakage Detection in Dikes and Concrete Structure Strain Monitoring

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Jean-Marie Henault ◽  
Gautier Moreau ◽  
Sylvain Blairon ◽  
Jean Salin ◽  
Jean-Robert Courivaud ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Brillouin Scattering ◽  
Optical Fiber Sensors ◽  
Leakage Detection ◽  
Strain Sensing ◽  
Water Leakage ◽  
Fiber Sensors ◽  
Practical Applications ◽  
Water Leakage Detection

Although optical fiber sensors have been developed for 30 years, there is a gap between lab experiments and field applications. This article focuses on specific methods developed to evaluate the whole sensing chain, with an emphasis on (i) commercially-available optoelectronic instruments and (ii) sensing cable. A number of additional considerations for a successful pairing of these two must be taken into account for successful field applications. These considerations are further developed within this article and illustrated with practical applications of water leakage detection in dikes and concrete structures monitoring, making use of distributed temperature and strain sensing based on Rayleigh, Raman, and Brillouin scattering in optical fibers. They include an adequate choice of working wavelengths, dedicated localization processes, choices of connector type, and further include a useful selection of traditional reference sensors to be installed nearby the optical fiber sensors, as well as temperature compensation in case of strain sensing.

scholarly journals Long-Range Distributed Solar Irradiance Sensing Using Optical Fibers

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 908 ◽  
Author(s):  
Regina Magalhães ◽  
Luis Costa ◽  
Sonia Martin-Lopez ◽  
Miguel Gonzalez-Herraez ◽  
Alejandro F. Braña ◽  
...  
Keyword(s):  
Solar Energy ◽  
Optical Fiber ◽  
Real Time ◽  
Long Range ◽  
Optical Fibers ◽  
Solar Irradiance ◽  
High Sensitivity ◽  
Ground Level ◽  
Solar Simulator ◽  
Distributed Sensor

Until recently, the amount of solar irradiance reaching the Earth surface was considered to be a steady value over the years. However, there is increasing observational evidence showing that this quantity undergoes substantial variations over time, which need to be addressed in different scenarios ranging from climate change to solar energy applications. With the growing interest in developing solar energy technology with enhanced efficiency and optimized management, the monitoring of solar irradiance at the ground level is now considered to be a fundamental input in the pursuit of that goal. Here, we propose the first fiber-based distributed sensor able of monitoring ground solar irradiance in real time, with meter scale spatial resolutions over distances of several tens of kilometers (up to 100 km). The technique is based on an optical fiber reflectometry technique (CP-ϕOTDR), which enables real time and long-range high-sensitivity bolometric measurements of solar radiance with a single optical fiber cable and a single interrogator unit. The method is explained and analyzed theoretically. A validation of the method is proposed using a solar simulator irradiating standard optical fibers, where we demonstrate the ability to detect and quantify solar irradiance with less than a 0.1 W/m2 resolution.

scholarly journals Effect of humidity on optical fiber distributed sensor based on Brillouin scattering

2008 ◽  
Author(s):  
Carlos A. Galindez ◽  
Francisco J. Madruga ◽  
M. Lomer ◽  
A. Cobo ◽  
Jose M. Lopez-Higuera
Keyword(s):  
Optical Fiber ◽  
Brillouin Scattering ◽  
Distributed Sensor

PREMODULATION-FREE MICROWAVE FREQUENCY UP/DOWN-CONVERSION USING OPTICAL-FIBER-STIMULATED BRILLOUIN SCATTERING

2009 ◽  
Vol 18 (04) ◽  
pp. 701-707 ◽  
Author(s):  
YING GAO ◽  
SHIMING GAO
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Microwave Frequency ◽  
Microwave Signal ◽  
Optical Carrier ◽  
All Optical ◽  
Stimulated Brillouin ◽  
Down Conversion

An all-optical premodulation-free microwave frequency up/down-conversion method is presented based on stimulated Brillouin scattering in optical fibers for bidirection radio-over-fiber systems. Through optical heterodyning between the modulated optical carrier and the Stokes light, the microwave signal of 1.5 GHz is up-converted to 9 and 12 GHz, and the microwave signal of 9 GHz is down-converted to 1.5 GHz. The unexpected microwaves are more than 7 dB suppressed by loading the signal to convert with the optical-carrier-suppressed modulation.

scholarly journals Annular Cavity Design for Photoluminescent Polymer Optical Fiber Sensors

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5199
Author(s):  
Rune Inglev ◽  
Jakob Janting ◽  
Ole Bang
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Single Point ◽  
Polymer Fibers ◽  
Polymer Optical Fiber ◽  
Sensing Matrix ◽  
Fiber Sensors ◽  
Fiber Design ◽  
Cavity Design ◽  
Good Agreement

We present optimization results on the design of a polymer optical fiber single point sensor suitable for photoluminescence-based sensing. The single point sensing design consists of one or two annular cavities, separated by a small distance, milled into the fiber and subsequently filled with a thick solution of polymer, solvent, and photoluminescent molecules, which is then allowed to dry. The design is tested by varying the depth and length of a single cavity and utilizing two cavities with varying separations. Results from experiments show a maximum response at a separation of 2 mm for which we present an analytical explanation. A geometrical, numerical simulation model, taking into account both skew and meridional rays, is developed and shows very good agreement with the experimental results. The fiber design presents a general platform that has the potential for the fabrication of multi-point photoluminescent sensors, for which it is necessary to have several points along the fiber functionalized for sensing. Furthermore, the approach with polymer fibers and polymer sensing gels allows for a robust integration of the sensing matrix and the optical fiber, more so than is possible using glass optical fibers.

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