Sensors

19 pages, 5550 KiB

Open AccessArticle

Nearshore Contamination Monitoring in Sandy Soils Using Polymer Optical Fibre Bragg Grating Sensing Systems

by Sina Fadaie, Moura Mehravar, David John Webb and Wei Zhang

Sensors 2022, 22(14), 5213; https://doi.org/10.3390/s22145213 - 12 Jul 2022

Cited by 4 | Viewed by 2047

Civil engineering assets and geo-structures continually deteriorate during their lifetime, particularly in harsh environments that may be contaminated with corrosive substances. However, efficient and constant structural health monitoring and accurate prediction of the service-life of these assets can help to ensure their safety, [...] Read more.

Civil engineering assets and geo-structures continually deteriorate during their lifetime, particularly in harsh environments that may be contaminated with corrosive substances. However, efficient and constant structural health monitoring and accurate prediction of the service-life of these assets can help to ensure their safety, performance, and health conditions and enable proper maintenance and rehabilitation. Nowadays, many of the largest cities throughout the world are situated in coastal zones, leading to a dramatic increase in the construction of nearshore geo-structures/infrastructures which are vulnerable to corrosion attacks resulting from salinity contamination. Additionally, seawater intrusion can threaten the quality and the sustainability of fresh groundwater resources, which are a crucial resource in coastal areas. To address these issues, detection of salinity in soil utilizing a novel polymer optical fibre Bragg grating (POFBG) sensor was investigated in this research. Experiments were carried out at different soil water contents with different salinities to assess the sensor’s response in a representative soil environment. The sensitivity of the POFBG sensor to salinity concentrations in water and soil environment is estimated as 58 ± 2 pm/%. The average standard error value in salinity is calculated as 0.43% for the samples with different soil water contents. The results demonstrate that the sensor is a promising and practical tool for the measurement and monitoring with high precision of salinity contamination in soil. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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14 pages, 5870 KiB

Open AccessArticle

Shaping Beam Profiles Using Plastic Optical Fiber Tapers with Application to Ice Sensors

by Kostas Amoiropoulos, Georgia Kioselaki, Nikolaos Kourkoumelis and Aris Ikiades

Sensors 2020, 20(9), 2503; https://doi.org/10.3390/s20092503 - 28 Apr 2020

Cited by 8 | Viewed by 3025

Abstract

Using either bulk or fiber optics the profile of laser beams can be altered from Gaussian to top-hat or hollow beams allowing enhanced performance in applications like laser cooling, optical trapping, and fiber sensing. Here, we report a method based on multimode Plastic [...] Read more.

Using either bulk or fiber optics the profile of laser beams can be altered from Gaussian to top-hat or hollow beams allowing enhanced performance in applications like laser cooling, optical trapping, and fiber sensing. Here, we report a method based on multimode Plastic Optical Fibers (POF) long-tapers, to tweak the beam profile from near Gaussian to a hollow beam, by generating surface irregularities on the conical sections of the taper with a heat-and-pull technique. Furthermore, a cutback technique applied on long tapers expanded the output beam profile by more than twice the numerical aperture (NA) of the fiber. The enhanced sensitivity and detection efficiency of the extended profile was tested on a fiber optical ice sensor related to aviation safety. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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12 pages, 4174 KiB

Open AccessCommunication

An Enhanced Plastic Optical Fiber-Based Surface Plasmon Resonance Sensor with a Double-Sided Polished Structure

by Lian Liu, Shijie Deng, Jie Zheng, Libo Yuan, Hongchang Deng and Chuanxin Teng

Sensors 2021, 21(4), 1516; https://doi.org/10.3390/s21041516 - 22 Feb 2021

Cited by 22 | Viewed by 2942

Abstract

An enhanced plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed by employing a double-sided polished structure. The sensor is fabricated by polishing two sides of the POF symmetrically along with the fiber axis, and a layer of Au film is [...] Read more.

An enhanced plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed by employing a double-sided polished structure. The sensor is fabricated by polishing two sides of the POF symmetrically along with the fiber axis, and a layer of Au film is deposited on each side of the polished region. The SPR can be excited on both polished surfaces with Au film coating, and the number of light reflections will be increased by using this structure. The simulation and experimental results show that the proposed sensor has an enhanced SPR effect. The visibility and full width at half maximum (FWHM) of spectrum can be improved for the high measured refractive index (RI). A sensitivity of 4284.8 nm/RIU is obtained for the double-sided POF-based SPR sensor when the measured liquid RI is 1.42. The proposed SPR sensor is easy fabrication and low cost, which can provide a larger measurement range and action area to the measured samples, and it has potential application prospects in the oil industry and biochemical sensing fields. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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11 pages, 2218 KiB

Open AccessArticle

Hydrogel-Core Microstructured Polymer Optical Fibers for Selective Fiber Enhanced Raman Spectroscopy

by Mikel Azkune, Igor Ayesta, Leire Ruiz-Rubio, Eneko Arrospide, Jose Luis Vilas-Vilela and Joseba Zubia

Sensors 2021, 21(5), 1845; https://doi.org/10.3390/s21051845 - 06 Mar 2021

Cited by 1 | Viewed by 2168

Abstract

A new approach of Fiber Enhanced Raman Spectroscopy (FERS) is described within this article based on the use of Hydrogel-Core microstructured Polymer Optical Fibers (HyC-mPOF). The incorporation of the hydrogel only on the core of the Hollow-Core microstructured Polymer Optical Fiber (HC-mPOF) enables [...] Read more.

A new approach of Fiber Enhanced Raman Spectroscopy (FERS) is described within this article based on the use of Hydrogel-Core microstructured Polymer Optical Fibers (HyC-mPOF). The incorporation of the hydrogel only on the core of the Hollow-Core microstructured Polymer Optical Fiber (HC-mPOF) enables to perform FERS measurements in a functionalized matrix, enabling high selectivity Raman measurements. The hydrogel formation was continuously monitored and quantified using a Principal Component Analysis verifying the coherence between the components and the Raman spectrum of the hydrogel. The performed measurements with high and low affinity target molecules prove the feasibility of the presented HyC-mPOF platform. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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13 pages, 1735 KiB

Open AccessArticle

Upconversion Nanocrystal Doped Polymer Fiber Thermometer

by Jonas Thiem, Simon Spelthann, Laurie Neumann, Florian Jakobs, Hans-Hermann Johannes, Wolfgang Kowalsky, Dietmar Kracht, Joerg Neumann, Axel Ruehl and Detlev Ristau

Sensors 2020, 20(21), 6048; https://doi.org/10.3390/s20216048 - 24 Oct 2020

Cited by 7 | Viewed by 2812

Abstract

In recent years, lanthanide-doped nanothermometers have been mainly used in thin films or dispersed in organic solvents. However, both approaches have disadvantages such as the short interaction lengths of the active material with the pump beam or complicated handling, which can directly affect [...] Read more.

In recent years, lanthanide-doped nanothermometers have been mainly used in thin films or dispersed in organic solvents. However, both approaches have disadvantages such as the short interaction lengths of the active material with the pump beam or complicated handling, which can directly affect the achievable temperature resolution. We investigated the usability of a polymer fiber doped with upconversion nanocrystals as a thermometer. The fiber was excited with a wavelength stabilized diode laser at a wavelength of 976 nm. Emission spectra were recorded in a temperature range from 10 to 35

^{\circ}

C and the thermal emission changes were measured. Additionally, the pump power was varied to study the effect of self-induced heating on the thermometer specifications. Our fiber sensor shows a maximal thermal sensitivity of 1.45%/K and the minimal thermal resolution is below 20 mK. These results demonstrate that polymer fibers doped with nanocrystals constitute an attractive alternative to conventional fluorescence thermometers, as they add a long pump interaction length while also being insensitive to strong electrical fields or inert to bio-chemical environments. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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9 pages, 2481 KiB

Open AccessLetter

Bend-Direction and Rotation Plastic Optical Fiber Sensor

by Demetrio Sartiano, Thomas Geernaert, Elena Torres Roca and Salvador Sales

Sensors 2020, 20(18), 5405; https://doi.org/10.3390/s20185405 - 21 Sep 2020

Cited by 6 | Viewed by 2410

Abstract

A plastic filament of poly (methyl methacrylate) (PMMA) was fabricated by extrusion. The mode confinement was simulated using numerical software. The idea is to study how the light intensity changes inside the plastic optical fiber (POF) when a bending in multiple directions is [...] Read more.

A plastic filament of poly (methyl methacrylate) (PMMA) was fabricated by extrusion. The mode confinement was simulated using numerical software. The idea is to study how the light intensity changes inside the plastic optical fiber (POF) when a bending in multiple directions is applied. The results obtained from the simulation were compared to the experimental observations. The non-circular shape of the POF allows sensing a rotation applied as well. The angle of rotation was obtained processing two images of the end facet of the fiber (one with the fiber in a reference position and one with the rotated fiber), using an intensity-based automatic image registration. The accuracy in the rotation calculation was of 0.01°. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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15 pages, 3962 KiB

Open AccessArticle

Polymer Optical Fiber Plantar Pressure Sensors: Design and Validation

by Sahar Safarloo, Arántzazu Núñez-Cascajero, Ruben Sanchez-Gomez and Carmen Vázquez

Sensors 2022, 22(10), 3883; https://doi.org/10.3390/s22103883 - 20 May 2022

Cited by 4 | Viewed by 1908

Abstract

The proper measurement of plantar pressure during gait is critical for the clinical diagnosis of foot problems. Force platforms and wearable devices have been developed to study gait patterns during walking or running. However, these devices are often expensive, cumbersome, or have boundary [...] Read more.

The proper measurement of plantar pressure during gait is critical for the clinical diagnosis of foot problems. Force platforms and wearable devices have been developed to study gait patterns during walking or running. However, these devices are often expensive, cumbersome, or have boundary constraints that limit the participant’s motions. Recent advancements in the quality of plastic optical fiber (POF) have made it possible to manufacture a low-cost bend sensor with a novel design for use in plantar pressure monitoring. An intensity-based POF bend sensor is not only lightweight, non-invasive, and easy to construct, but it also produces a signal that requires almost no processing. In this work, we have designed, fabricated, and characterized a novel intensity POF sensor to detect the force applied by the human foot and measure the gait pattern. The sensors were put through a series of dynamic and static tests to determine their measurement range, sensitivity, and linearity, and their response was compared to that of two different commercial force sensors, including piezo resistive sensors and a clinical force platform. The results suggest that this novel POF bend sensor can be used in a wide range of applications, given its low cost and non-invasive nature. Feedback walking monitoring for ulcer prevention or sports performance could be just one of those applications. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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10 pages, 1117 KiB

Open AccessArticle

Towards Highly Efficient Polymer Fiber Laser Sources for Integrated Photonic Sensors

by Simon Spelthann, Stefanie Unland, Jonas Thiem, Florian Jakobs, Jana Kielhorn, Pen Yiao Ang, Hans-Hermann Johannes, Dietmar Kracht, Joerg Neumann, Axel Ruehl, Wolfgang Kowalsky and Detlev Ristau

Sensors 2020, 20(15), 4086; https://doi.org/10.3390/s20154086 - 22 Jul 2020

Cited by 5 | Viewed by 2470

Abstract

Lab-on-a-Chip (LoC) devices combining microfluidic analyte provision with integrated optical analysis are highly desirable for several applications in biological or medical sciences. While the microfluidic approach is already broadly addressed, some work needs to be done regarding the integrated optics, especially provision of [...] Read more.

Lab-on-a-Chip (LoC) devices combining microfluidic analyte provision with integrated optical analysis are highly desirable for several applications in biological or medical sciences. While the microfluidic approach is already broadly addressed, some work needs to be done regarding the integrated optics, especially provision of highly integrable laser sources. Polymer optical fiber (POF) lasers represent an alignment-free, rugged, and flexible technology platform. Additionally, POFs are intrinsically compatible to polymer microfluidic devices. Home-made Rhodamine B (RB)-doped POFs were characterized with experimental and numerical parameter studies on their lasing potential. High output energies of 1.65 mJ, high slope efficiencies of

56 %

, and

50 %

-lifetimes of ≥900 k shots were extracted from RB:POFs. Furthermore, RB:POFs show broad spectral tunability over several tens of nanometers. A route to optimize polymer fiber lasers is revealed, providing functionality for a broad range of LoC devices. Spectral tunability, high efficiencies, and output energies enable a broad field of LoC applications. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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26 pages, 6882 KiB

Open AccessArticle

Sensing Applications in Aircrafts Using Polymer Optical Fibres

by Pedro C. Lallana, Gotzon Aldabaldetreku, Alicia López, David S. Montero, Gaizka Durana, Javier Mateo, M. Ángeles Losada, Joseba Zubia and Carmen Vázquez

Sensors 2021, 21(11), 3605; https://doi.org/10.3390/s21113605 - 21 May 2021

Cited by 5 | Viewed by 2866

Abstract

We report on recent advances in the use of inexpensive polymer optical fibres (POFs) for sensing applications in avionics. The sensors analysed in this manuscript take advantage of the unique properties of polymers, such as high flexibility, elasticity, and sensitivity, and they range [...] Read more.

We report on recent advances in the use of inexpensive polymer optical fibres (POFs) for sensing applications in avionics. The sensors analysed in this manuscript take advantage of the unique properties of polymers, such as high flexibility, elasticity, and sensitivity, and they range from strain, elongation, and vibration interrogators to level and temperature meters, leading to cost-effective techniques for structural health monitoring in aircraft structures. We also highlight recent power-supply methods using Power-over-POF in order to feed sensors remotely, and we discuss the constraints imposed by connectors on the performance of POF networks in aircrafts. Full article

(This article belongs to the Special Issue Recent Development and Applications of Plastic Optical Fiber Sensors)

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