Bending loss of optical fibers: transduction mechanism for fiber-optic sensors

1983 ◽  
Author(s):  
N. Lagakos ◽  
D. S. Czaplak ◽  
J. H. Cole ◽  
J. A. Bucaro ◽  
E. L. Green
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Transduction Mechanism ◽  
Bending Loss

Automated Fiber-Optic System for Monitoring the Stability of the Pit Quarry Mass and Dumps

2021 ◽  
pp. 19-26
Author(s):  
А.D. Меkhtiyev ◽  
◽  
E.G. Neshina ◽  
P.Sh. Madi ◽  
D.A. Gorokhov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Light Wave ◽  
Single Mode ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Laboratory Sample ◽  
Single Mode Optical Fiber

This article ls with the issues related to the development of a system for monitoring the deformation and displacement of the rock mass leading to the collapse of the quarry sides. Monitoring system uses point-to-point fiber-optic sensors. Fiber-optic sensors and control cables of the communication line are made based on the single mode optical fibers, which allows to measure with high accuracy the deformations and displacements of the rock mass at a distance of 30-50 km. To create fiber-optic pressure sensors, an optical fiber of the ITU-T G. 652.D standard is used. Laboratory sample is developed concerning the point fiber-optic sensor made based on the two-arm Mach-Zender interferometer using a single mode optical fiber for monitoring strain (displacements) with a change in the sensitivity and a reduced influence of temperature interference leading to zero drift. The article presents a mathematical apparatus for calculating the intensity of radiation of a light wave passing through an optical fiber with and without mechanical stress. A laboratory sample of single mode optical fibers based on the Mach-Zender interferometer showed a fairly high linearity and accuracy in the measurement and can be used to control the strain of the mass after appropriate refinement of its design. Mathematical expressions are also given for determining the intensity of the light wave when the distance between the fixing points of a single mode optical fiber changes depending on the change in the external temperature. A diagram for measuring strain using a point fiber-optic strain sensor is developed. Hardware and software package is developed, which can be used to perform a number of settings of measuring channels. The work is aimed at solving the production problems of the Kenzhem quarry of AK Altynalmas JSC.

A Step-Index Multimode Fiber-Optic Microbend Displacement Sensor Wavelength Dependent Loss

2019 ◽  
pp. 47-60
Author(s):  
Sami D. Alaruri
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Transmission Loss ◽  
Wavelength Dependence ◽  
Fiber Optic Sensors ◽  
Fused Silica ◽  
Displacement Sensor ◽  
Sensor Output ◽  
Core Diameter ◽  
Step Index

In this chapter, the wavelength dependence of bend loss in a step-index multimode optical fiber (100 µm core diameter; fused silica) was investigated for fiber bend radii ranging between 2.0 and 4.5 mm using six laser excitation wavelengths, namely, 337.1, 470, 590, 632.8, 750, and 810 nm. The results obtained from fitting the bend loss measurements to Kao's model and utilizing MATLAB® indicate that bend loss is wavelength dependent and transmission loss in multimode optical fibers increases with the decrease in the fiber bend radius. Furthermore, the response of a microbend fiber-optic displacement sensor was characterized at 337.1, 470, 632.8, 750, and 810 nm. Measurements obtained from the microbend sensor indicate that the sensor output power is linear with the applied displacement and the sensor output is wavelength dependent. Lastly, references for industrial and biomedical applications of microbend fiber-optic sensors are provided. Finally, a brief description for the transmission loss mechanisms in optical fibers is given.

Integrated Fiber Optic Sensors For Nondestructive Characterization Of Concrete Structures

1997 ◽  
Vol 503 ◽  
Author(s):  
F. Ansari
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Optical Fiber Sensor ◽  
Fiber Optic Sensors ◽  
Fiber Sensors ◽  
Fully Integrated ◽  
Integrated Optical ◽  
Concrete Elements

ABSTRACTIt is possible to monitor the initiation and progress of various mechanical or environmentally induced perturbations in concrete elements by way of fully integrated optical fiber sensors. Geometric adaptability and ease by which optical fibers can be embedded within concrete elements has led to the development of a number of innovative applications for concrete elements. This article is intended for a brief introduction into the theories, principles, and applications of fiber optic sensors as they pertain to applications in concrete.. However, due to the fact that the transduction mechanism in optical fibers is invariant of the materials employed, the principles introduced here also correspond to other structural materials. The only application related differences among various materials pertain to sensitivity and choice of optical fiber sensor types.

In situ determination of the complex permittivity of ultrathin H2-infused palladium coatings for plasmonic fiber optic sensors in the near infrared

2018 ◽  
Vol 6 (19) ◽  
pp. 5161-5170 ◽  
Author(s):  
Xuejun Zhang ◽  
Shunshuo Cai ◽  
Fu Liu ◽  
Hao Chen ◽  
Peiguang Yan ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Complex Permittivity ◽  
Near Infrared ◽  
Fiber Optic ◽  
Fiber Optic Sensors

In situ determination of the complex permittivity of H2-infused palladium using near infrared plasmons over optical fibers.

scholarly journals Distributed fiber optic radiation sensors

2021 ◽  
Vol 1 ◽  
pp. 15-16
Author(s):  
Aleksander Wosniok ◽  
Katerina Krebber
Keyword(s):  
Refractive Index ◽  
Real Time ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Radiation Monitoring ◽  
High Radiation ◽  
Fiber Core ◽  
Radiation Induced ◽  
Radiation Sensors

Abstract. The international research efforts focused on the development of radiation sensors based on optic fibers have their origins in the 1970s (Evans et al., 1978). Generally, the lightweight fiber optic sensors are immune to electromagnetic field interference and high voltages making them deployable in harsh environments at hard to reach areas where conventional sensors usually will not work at all. A further advantage of such radiation sensors is the possibility of remote and real-time monitoring (Huston et al., 2001). In this work, we present our results achieved in several research activities for development of fiber optic dosimeters. The findings show that both the measurement of the radiation-induced attenuation (RIA) along the entire sensing fiber and the accompanying change in the refractive index of the fiber core can be used for distributed radiation monitoring in the kGy and MGy range, respectively. Depending on the fiber type and material the RIA shows varying response to dose rates, environmental temperatures and the wavelength of the laser source used. Thereby, an operation with visible laser light provides most favorable performance in terms of high radiation sensitivity. Operating at these wavelengths, RIA monitoring could yield high-sensitivity dose measurement with sub-gray resolution and accuracy (Stajanca and Krebber, 2017b); however, conventional optical time-domain reflectometry (OTDR) systems for RIA measurements operating in the visible range suffer from low-spatial resolution, long measurement times and poor signal-to-noise (SNR) ratio. The limitations of the OTDR performance can be overcome by the incoherent optical frequency domain reflectometry (I-OFDR) developed by the Federal Institute of Materials Research and Testing (BAM, Liehr et al., 2009) with potential for dynamic real-time measurement. Over the years, several highly radiation sensitive fibers, such as perfluorinated polymer optical fibers (PF-POF, Stajanca and Krebber, 2017a), phosphorous-doped silica optical fibers (SOF, Paul et al., 2009), aluminium-doped SOF (Faustov et al., 2013) and erbium-doped SOF (Wosniok et al., 2016) have been identified and are commercially available. As mentioned before, the radiation-induced RIA increase is associated with an increase in the refractive index leading also to material compaction in the fiber core. The latter two effects can be used for measuring radiation distribution based on Brillouin scattering in the range of high radiation doses of several MGy (Phéron et al., 2012; Wosniok et al., 2016). When using fiber optic sensors for radiation monitoring, the existing post-irradiation annealing behavior of the optical fiber sensors must also be considered.

Evanescent Wave Absorption Spectroscopy by Means of Bi-Tapered Multimode Optical Fibers

1998 ◽  
Vol 52 (4) ◽  
pp. 546-551 ◽  
Author(s):  
Anna Grazia Mignani ◽  
Riccardo Falciai ◽  
Leonardo Ciaccheri
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Absorption Spectroscopy ◽  
Evanescent Wave ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Experimental Results ◽  
Multimode Optical Fiber ◽  
Wave Absorption ◽  
Reproducible Technique

This paper discusses the theoretical and experimental implications of tapering a multimode optical fiber with a view to its use in evanescent wave absorption spectroscopy. Good experimental results are obtained, showing the possibility of quadruplicating the absorbance efficiency. This easy and reproducible technique for taper fabrication is suitable for the implementation of both probes for spectroscopy and chemically assisted fiber-optic sensors.

Application of Brillouin Fiber Optic Sensors to Monitor Pipeline Integrity

2004 ◽  
Author(s):  
R. C. Tennyson ◽  
W. D. Morison ◽  
B. Colpitts ◽  
A. Brown
Keyword(s):  
Optical Fibers ◽  
Continuous Monitoring ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Third Party ◽  
Ground Movement ◽  
Temperature Profiles ◽  
Thermal Anomalies ◽  
Temperature Distributions ◽  
Close Proximity

This paper describes the application of Brillouin fiber optic sensors to monitor pipeline integrity in terms of third party intrusion, leak detection, and ground movement. Brillouin sensors provide a means for continuous monitoring of strain and temperature distributions over distances of about 25km. The optical fibers can be bonded to the pipeline or buried in close proximity to the pipe. Third party intrusion is detected by strain anomalies caused by vehicles or persons in close proximity to the sensor located at some depth below the surface. Leaks from oil or gas pipelines are detected by thermal anomalies in the temperature profiles. Pipeline movement can also be detected using this system for existing and new pipeline installations. Applications include northern pipelines, high consequence areas, river crossings and fault lines.

scholarly journals Liquid crystal cell with a tapered optical fiber as an active element to optical applications

2019 ◽  
Vol 11 (1) ◽  
pp. 13
Author(s):  
Joanna Ewa Moś ◽  
Karol Antoni Stasiewicz ◽  
Leszek Roman Jaroszewicz
Keyword(s):  
Liquid Crystal ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
High Sensitivity ◽  
Single Mode ◽  
Fiber Optic Sensors ◽  
Liquid Crystal Cell ◽  
Crystal Cell ◽  
Tapered Optical Fiber

The work describes the technology of a liquid crystal cell with a tapered optical fiber as an element providing light. The tapered optical fiber with the total optical loss of 0.22 ± 0.07 dB, the taper waist diameter of 15.5 ± 0.5 μm, and the elongation of 20.4 ± 0.3 mm has been used. The experimental results are presented for a liquid crystal cell filled with a mixture 1550* for parallel orientation of LC molecules to the cross section of the taper waist. Measurement results show the influence of the electrical field with voltage in the range of 0-200 V, without, as well as with different modulation for spectral characteristics. The sinusoidal and square signal shapes are used with a 1-10 Hz frequency range. Full Text: PDF ReferencesZ. Liu, H. Y. Tam, L. Htein, M. L.Vincent Tse, C. Lu, "Microstructured Optical Fiber Sensors", J. Lightwave Technol. 35, 16 (2017). CrossRef T. R. Wolinski, K. Szaniawska, S. Ertman1, P. Lesiak, A. W. Domański, R. Dabrowski, E. Nowinowski-Kruszelnicki, J. 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Huang, F.Zou, Y.Dong, T.Wang, "High sensitivity refractive index sensor based on adiabatic tapered optical fiber deposited with nanofilm by ALD", Opt. Express 23, 11 (2015). CrossRef L. Zhang, J. Lou, L. Tong, "Micro/nanofiber optical sensors", Photonics sensor 1, 1 (2011). CrossRef L.Tong, J. Lou, E. Mazur, "Single-mode guiding properties of subwavelength-diameter silica and silicon wire waveguides", Opt. Express 11, 6 (2004). CrossRef H. Moyyed, I. T. Leite, L. Coelho, J. L. Santos, D. Viegas, "Analysis of phase interrogated SPR fiber optic sensors with bimetallic layers", IEEE Sensors Journal 14, 10 (2014). CrossRef A. González-Cano, M. Cruz Navarette, Ó. Esteban, N. Diaz Herrera , "Plasmonic sensors based on doubly-deposited tapered optical fibers", Sensors 14, 3 (2014). CrossRef K. A. Stasiewicz, J.E. Moś, "Threshold temperature optical fibre sensors", Opt. Fiber Technol. 32, (2016). CrossRef L. Zhang, F. Gu, J. Lou, X. Yin, L. Tong, "Fast detection of humidity with a subwavelength-diameter fiber taper coated with gelatin film", Opt. Express 16, 17 (2008). CrossRef S.Zhu, F.Pang, S. Huang, F. Zou, Q. Guo, J. Wen, T. Wang, "High Sensitivity Refractometer Based on TiO2-Coated Adiabatic Tapered Optical Fiber via ALD Technology", Sensors 16, 8 (2016). CrossRef G.Brambilla, "Optical fibre nanowires and microwires: a review", J. Optics 12, 4 (2010) CrossRef M. Ahmad, L.L. Hench, "Effect of taper geometries and launch angle on evanescent wave penetration depth in optical fibers", Biosens. Bioelectron. 20, 7 (2005). CrossRef L.M. Blinov, Electrooptic Effects in Liquid Crystal Materials (New York, Springftianer, 1994). CrossRef L. Scolari, T.T. Alkeskjold, A. Bjarklev, "Tunable Gaussian filter based on tapered liquid crystal photonic bandgap fibre", Electron. Lett. 42, 22 (2006). CrossRef J. Moś, M. Florek, K. Garbat, K.A. Stasiewicz, N. Bennis, L.R. Jaroszewicz, "In-Line Tunable Nematic Liquid Crystal Fiber Optic Device", J. of Lightwave Technol. 36, 4 (2017). CrossRef J. Moś, K A Stasiewicz, K Garbat, P Morawiak, W Piecek, L R Jaroszewicz, "Tapered fiber liquid crystal hybrid broad band device", Phys. Scripta. 93, 12 (2018). CrossRef Ch. Veilleux, J. Lapierre, J. Bures, "Liquid-crystal-clad tapered fibers", Opt. Lett. 11, 11 (1986). CrossRef R. Dąbrowski, K. Garbat, S. Urban, T.R. Woliński, J. Dziaduszek, T. Ogrodnik, A,Siarkowska, "Low-birefringence liquid crystal mixtures for photonic liquid crystal fibres application", Liq. Cryst. 44, (2017). CrossRef S. Lacroix, R. J. Black, Ch. Veilleux, J. Lapierre, "Tapered single-mode fibers: external refractive-index dependence", Appl. Opt., 25, 15 (1986). CrossRef J.F. Henninot, D. Louvergneaux , N.Tabiryan, M. Warenghem, "Controlled Leakage of a Tapered Optical Fiber with Liquid Crystal Cladding", Mol. Cryst.and Liq.Cryst., 282, 1(1996). CrossRef

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