Chromophore Dynamics in Sol-Gel Glasses and Xerogel Clad Fiber Optic Sensors

1994 ◽  
Vol 346 ◽  
Author(s):  
Drew L'Esperance ◽  
Clarice A. Browne ◽  
Eric L. Chronister
Keyword(s):  
Energy Transfer ◽  
Fiber Optic ◽  
Rotational Diffusion ◽  
Sol Gel ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Time Resolved ◽  
Optic Sensor ◽  
Sensor Device ◽  
Gel Glasses

ABSTRACTTime-resolved depolarization measurements are used to investigate rotational diffusion and optical energy transfer dynamics of chromophores incorporated into silica and aluminosilica solutions, gels, and glasses. The use of an organically doped sol-gel clad waveguide as a novel intrinsic fiber optic sensor device is also demonstrated, and advantages of time-resolved detection of the fiber optic sensor are illustrated.

scholarly journals Ex-Vivo Measurement of the pH in Aqueous Humor Samples by a Tapered Fiber-Optic Sensor

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5075
Author(s):  
Ondřej Podrazký ◽  
Jan Mrázek ◽  
Jana Proboštová ◽  
Soňa Vytykáčová ◽  
Ivan Kašík ◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Aqueous Humor ◽  
Fiber Optic ◽  
Ex Vivo ◽  
Sol Gel ◽  
Ph Sensor ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Tapered Optical Fiber ◽  
Practical Demonstration

A practical demonstration of pH measurement in real biological samples with an in-house developed fiber-optic pH sensor system is presented. The sensor uses 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) fluorescent dye as the opto-chemical transducer. The dye is immobilized in a hybrid sol-gel matrix at the tip of a tapered optical fiber. We used 405 nm and 450 nm laser diodes for the dye excitation and a photomultiplier tube as a detector. The sensor was used for the measurement of pH in human aqueous humor samples during cataract surgery. Two groups of patients were tested, one underwent conventional phacoemulsification removal of the lens while the other was subjected to femtosecond laser assisted cataract surgery (FLACS). The precision of the measurement was ±0.04 pH units. The average pH of the aqueous humor of patients subjected to FLACS and those subjected to phacoemulsification were 7.24 ± 0.17 and 7.31 ± 0.20 respectively.

Sol-Gel and RF Sputtering Thin Film Coatings for Fiber Optic Sensor Applications

1991 ◽  
Vol 244 ◽  
Author(s):  
M. R. Shahriari ◽  
J. Y. Ding ◽  
C. M. Wang ◽  
C. H. Lin ◽  
G. H. Sigel
Keyword(s):  
Thin Film ◽  
Optical Waveguides ◽  
Fiber Optic ◽  
Sol Gel ◽  
Rf Sputtering ◽  
Silica Matrix ◽  
Hydrogen Gas ◽  
Fiber Optic Sensor ◽  
Sensor Applications ◽  
Optic Sensor

ABSTRACTThin film coating techniques appear to have many advantages over other techniques for immobilization and incorporation of chemical indicators to optical waveguides in developing dye based fiber optic chemical sensors. We have fabricated thin films of composites by using sol-gel and RF sputtering techniques. Different organic and inorganic indicators were immobilized in these films and incorporated into optical waveguides for sensor applications. A fiber optic pH sensor has been developed by introducing pH indicators into a silica matrix and coated as a thin film onto a porous glass fiber by a sol-gel technique. Also, a hydrogen gas fiber optic sensor has been developed by using a RF sputtered WO3/Pd coated porous optical fiber.

scholarly journals Questions of application of fiber-optic sensors for monitoring crack growth during rock deformations

2021 ◽  
Vol 2140 (1) ◽  
pp. 012037
Author(s):  
V V Yugay ◽  
P Sh Madi ◽  
S B Ozhigina ◽  
D A Gorokhov ◽  
A D Alkina
Keyword(s):  
Optical Fiber ◽  
Fiber Optic ◽  
Single Mode ◽  
Mechanical Action ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Mountain Range ◽  
Mining Equipment ◽  
Optic Sensor ◽  
Rock Deformations

Abstract The paper considers ways to solve the problem of developing a system for monitoring displacement in quarries, which are the main main cause of the collapse of boards and berms in quarries. To ensure safety and constant monitoring during work at the quarry, there are chiseled fiber-optic sensors. The fiber-optic sensor is made on the basis of a single-mode optical fiber, which makes it possible to measure the displacements of the mountain range at distances of about 30 km with high accuracy. Laboratory sample a fiber-optic sensor in its work uses a method for monitoring additional losses that occur during mechanical action on an optical fiber. The fiber-optic sensor was made to show a fairly high linearity and accuracy during measurements and can be used to control the deformation of the array after appropriate refinement of its design. This article is aimed at creating means of controlling the process of deformation and displacement of a mountain massif. Ultimately, the results of the study will help prevent accidents associated with the collapse of the sides. Since the growth of cracks in the rocks of the bort mountain massif leads to its sudden collapse and creates a significant danger for personnel, it also causes the failure of mining equipment.

Low-cost real-time fiber optic sensor for intrusion detection

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Adel Abdallah ◽  
Mohamed M. Fouad ◽  
Hesham N. Ahmed
Keyword(s):  
Signal Processing ◽  
Intrusion Detection ◽  
Real Time ◽  
Fiber Optic ◽  
Reference Signal ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Content Type ◽  
Intensity Modulated ◽  
Optic Sensor

Purpose The purpose of this paper is to introduce a novel intensity-modulated fiber optic sensor for real-time intrusion detection using a fiber-optic microbend sensor and an optical time-domain reflectometer (OTDR). Design/methodology/approach The proposed system is tested using different scenarios using person/car as intruders. Experiments are conducted in the lab and in the field. In the beginning, the OTDR trace is obtained and recorded as a reference signal without intrusion events. The second step is to capture the OTDR trace with intrusion events in one or multiple sectors. This measured signal is then compared to the reference signal and processed by matrix laboratory to determine the intruded sector. Information of the intrusion is displayed on an interactive screen implemented by Visual basic. The deformer is designed and implemented using SOLIDWORKS three-dimensional computer aided design Software. Findings The system is tested for intrusions by performing two experiments. The first experiment is performed for both persons (>50 kg) in the lab and cars in an open field with a car moving at 60 km/h using two optical fiber sectors of lengths 200 and 500 m. For test purposes, the deformer length used in the experiment is 2 m. The used signal processing technique in the first experiment has some limitations and its accuracy is 70% after measuring and recording 100 observations. To overcome these limitations, a second experiment with another technique of signal processing is performed. Research limitations/implications The system can perfectly display consecutive intrusions of the sectors, but in case of simultaneous intrusions of different sectors, which is difficult to take place in real situations, there will be the ambiguity of the number of intruders and the intruded sector. This will be addressed in future work. Suitable and stable laser power is required to get a suitable level of backscattered power. Optimization of the deformer is required to enhance the sensitivity and reliability of the sensor. Practical implications The proposed work enables us to benefit from the ease of implementation and the reduced cost of the intensity-modulated fiber optic sensors because it overcomes the constraints that prevent using the intensity-modulated fiber optic sensors for intrusion detection. Originality/value The proposed system is the first time long-range intensity-modulated fiber optic sensor for intrusion detection.

Fiber Optic Sensors for Monitoring Pipe Bending Due to Ground Movement

2006 ◽  
Author(s):  
Sam Cauchi ◽  
Thierry Cherpillod ◽  
Don Morison ◽  
Ed McClarty
Keyword(s):  
Fiber Optic ◽  
Monitoring Program ◽  
Fiber Optic Sensors ◽  
Ground Movement ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Coiled Fiber ◽  
Back Filling ◽  
Pipe Bending ◽  
Sour Gas

This paper describes an installation of fiber optic sensors designed to measure pipe bending due to ground movement at three sites on a 16” gas transmission line. The sour gas pipeline had failed in December, 2004 from excessive forces related to ground movement. As temporary mitigation the pipeline was daylighted to reduce the soil traction forces but a comprehensive monitoring program had to be developed before placing the pipeline back into conventional service. During the time when the section of pipeline was daylighted, three linear and three coiled fiber optic sensors were installed at each of three sites selected as part of a system designed to measure bending strains in the 0.01–1.0% range. The two types of sensors were placed in pairs approximately at the 12, 4, and 8 o’clock positions. Conventional vibrating wire (VW) strain gauges were also installed at the fiber optic sensor locations for comparison purposes. Slope inclinometers were installed at each of the instrumentation sites to correlate ground movement to pipe bending. Following pipeline re-coating, and back-filling, visits to the site were made at approximately monthly intervals to gather data at conveniently placed break-out boxes. The complete fiber optic sensor system functionality is described and results are presented that show how the raw strain data are transformed into bending using software that also serves as a secure database.

Simultaneous Measurement of Torsion and Curvature Using Curvature Fiber Optic Sensor

2008 ◽  
Vol 392-394 ◽  
pp. 448-453
Author(s):  
Y.L. Fu ◽  
H.T. Di
Keyword(s):  
Torsion Angle ◽  
Fiber Optic ◽  
Low Cost ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Optimal Direction ◽  
Maximal Sensitivity ◽  
Negative Bending ◽  
Torsion Deformation

Curvature fiber optic sensors are a kind of novel low cost sensors that can detect curvature directly and distinguish the positive bending and negative bending. This kind of sensor is used to detect torsion deformation of shaft in this paper. The optimal direction of curvature fiber optic sensor was analyzed in osculating plane and rectification plane and maximal sensitivity was gained. The results show that sensor response to the torsion angle is linear approximately. Torsion angle, curvature and bending direction of shaft were measured simultaneously by using curvature fiber optic sensors.

The Development and the Use of Fiber Optic Sensors for the Structural Health Monitoring of Composite (GFRP) Structures

2002 ◽  
Author(s):  
Evageline Rivera ◽  
Dimos Polyzois ◽  
Douglas J. Thomson ◽  
Ningguang Xu
Keyword(s):  
Structural Integrity ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Sensor Technology ◽  
Promising Alternative ◽  
Interferometric Sensors ◽  
Optic Sensor ◽  
Composite Glass ◽  
Path Lengths

The development of a fiber optic sensor system for the long-term monitoring of composite glass fiber-reinforced polymer (GFRP) poles will be presented. There is a growing interest in developing techniques for evaluating and monitoring their structural integrity. In the past few years, fiber optic sensor technology has emerged as a promising alternative to conventional methods of monitoring such as strain gauges. Fiber optic sensors can be attached to or embedded in civil structures such as bridges, dams and buildings. They operate by responding to changes in temperature and strain on the structure. The long gauge fiber optic sensor measures the average strain between two points on a structure. Long gauges are interferometric sensors that involve phase matching two optical paths to create a maximum interference pattern at the photodetector. The strain is calculated using the distance in which the reference arm of the interferometer is moved in order to match the optical path lengths.

scholarly journals Multiparameter miniature fiber-optic sensor: design and signal interrogation

2019 ◽  
pp. 255-261
Keyword(s):  
Optical Fibers ◽  
Path Length ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Independent Measurement ◽  
Optic Sensor ◽  
Highly Sensitive ◽  
Length Changes ◽  
Assembly Procedure

Miniature, all-silica, fiber-optic sensors capable of independent measurement of at least two different parameters are presented. Sensors were produced by a micromachining process based on the selective etching of specially designed phosphorousdoped optical fibers and an assembly-procedure that included fiber cleaving, fiber splicing and etching of fiber-micro-assemblies. Furthermore, an efficient method for independent readout of parameters in sensors that are composed of multiple resonators was also developed. The method utilizes a discrete Furrier transform of sensor’s optical spectrum and allows for simultaneous, crosstalk-free and highly sensitive readout of individual resonators’ path length changes.

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