scholarly journals Sensing Properties of Fused Silica Single-Mode Optical Fibers Based on PPP-BOTDA in High-Temperature Fields

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5021
Author(s):  
Jiahui Shen ◽  
Ting Li ◽  
Hong Zhu ◽  
Caiqian Yang ◽  
Kai Zhang

The strain of fiber-reinforced polymer (FRP) bars at high temperatures is currently difficult to measure. To overcome this difficulty, a method of smart FRP bars embedded with optical fibers was proposed and studied, in which an ordinary single-mode optical fiber was applied as a distributed sensor. In this paper, both the distributed temperature and strain-sensing characteristics of optical fiber were studied based on pulse pre-pump Brillouin optical time-domain analysis (PPP-BOTDA) under high temperature. The temperature and strain coefficients were investigated under a thermomechanical coupling environment with consideration of large strain levels. The experimental results show that the temperature and strain coefficients decreased as the temperature increased, because the properties of silica and coating materials changed with temperature. Then, the formulas for determining the temperature and strain coefficients at high temperatures were introduced and discussed. The excellent sensing performance of the optical fiber indicated that smart FRP bars have the potential for use at high temperatures.

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 521 ◽  
Author(s):  
Georgia Konstantinou ◽  
Karolina Milenko ◽  
Kyriaki Kosma ◽  
Stavros Pissadakis

We demonstrate a three-port, light guiding and routing T-shaped configuration based on the combination of whispering gallery modes (WGMs) and micro-structured optical fibers (MOFs). This system includes a single mode optical fiber taper (SOFT), a slightly tapered MOF and a BaTiO3 microsphere for efficient light coupling and routing between these two optical fibers. The BaTiO3 glass microsphere is semi-immersed into one of the hollow capillaries of the MOF taper, while the single mode optical fiber taper is placed perpendicularly to the latter and in contact with the equatorial region of the microsphere. Experimental results are presented for different excitation and reading conditions through the WGM microspherical resonator, namely, through single mode optical fiber taper or the MOF. The experimental results indicate that light coupling between the MOF and the single mode optical fiber taper is facilitated at specific wavelengths, supported by the light localization characteristics of the BaTiO3 glass microsphere, with spectral Q-factors varying between 4.5 × 103 and 6.1 × 103, depending on the port and parity excitation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. A. Perez-Herrera ◽  
M. Bravo ◽  
P. Roldan-Varona ◽  
D. Leandro ◽  
L. Rodriguez-Cobo ◽  
...  

AbstractIn this work, an experimental analysis of the performance of different types of quasi-randomly distributed reflectors inscribed into a single-mode fiber as a sensing mirror is presented. These artificially-controlled backscattering fiber reflectors are used in short linear cavity fiber lasers. In particular, laser emission and sensor application features are analyzed when employing optical tapered fibers, micro-drilled optical fibers and 50 μm-waist or 100 μm-waist micro-drilled tapered fibers (MDTF). Single-wavelength laser with an output power level of about 8.2 dBm and an optical signal-to-noise ratio of 45 dB were measured when employing a 50 μm-waist micro-drilled tapered optical fiber. The achieved temperature sensitivities were similar to those of FBGs; however, the strain sensitivity improved more than one order of magnitude in comparison with FBG sensors, attaining slope sensitivities as good as 18.1 pm/με when using a 50 μm-waist MDTF as distributed reflector.


Author(s):  
А.D. Меkhtiyev ◽  
◽  
E.G. Neshina ◽  
P.Sh. Madi ◽  
D.A. Gorokhov ◽  
...  

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.


Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 574 ◽  
Author(s):  
Ismail Laarossi ◽  
María Quintela-Incera ◽  
José López-Higuera

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.


2009 ◽  
Vol 20 (3) ◽  
pp. 034016 ◽  
Author(s):  
Sharon Kiesel ◽  
Kara Peters ◽  
Tasnim Hassan ◽  
Mervyn Kowalsky

2020 ◽  
Vol 2 (2) ◽  
pp. 91-99
Author(s):  
Imam Mulyanto

The test has been successfully carried out on optical fibers to be used as a macrobending tilt sensor using SMF-28 single mode optical fiber. The optical fiber was molded with silicon rubber, then connected to a laser light and a power meter to see the intensity of the laser power produced. The principle is carried out using the macro bending phenomenon on single mode optical fibers, where the laser light intensity in the fiber optic cable will decrease if there is a bend or bending in the fiber optic cable. We can observe the power loss resulting from the macro bending process to find out how sensitive the optical fiber is to changes in a given angle. The resulting optical fiber sensitivity value is -0.1534o/dBm.


Photonics ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 373
Author(s):  
Djamila Bouaziz ◽  
Grégoire Chabrol ◽  
Assia Guessoum ◽  
Nacer-Eddine Demagh ◽  
Sylvain Lecler

Shaped optical fiber tips have recently attracted a lot of interest for photonic jet light focusing due to their easy manipulation to scan a sample. However, lensed optical fibers are not new. This study analyzes how fiber tip parameters can be used to control focusing properties. Our study shows that the configurations to generate a photonic jet (PJ) can clearly be distinguished from more classical-lensed fibers focusing. PJ is a highly concentrated, propagative light beam, with a full width at half maximum (FWHM) that can be lower than the diffraction limit. According to the simulations, the PJs are obtained when light is coupled in the guide fundamental mode and when the base diameter of the microlens is close to the core diameter. For single mode fibers or fibers with a low number of modes, long tips with a relatively sharp shape achieve PJ with smaller widths. On the contrary, when the base diameter of the microlens is larger than the fiber core, the focus point tends to move away from the external surface of the fiber and has a larger width. In other words, the optical system (fiber/microlens) behaves in this case like a classical-lensed fiber with a larger focus spot size. The results of this study can be used as guidelines for the tailored fabrication of shaped optical fiber tips according to the targeted application.


2014 ◽  
Vol 656 ◽  
pp. 11-16
Author(s):  
Rochdi El Abdi ◽  
Irina Severin

Photosensitive single mode optical fibers have been embedded in composite sample in order to be used in optical sensors which monitor the health of civil engineering structure.A simple composite with epoxy vinyl ester matrix reinforced with E-glass unidirectional fibers was implemented using two embedded optical fibers. Interfacial adhesion stress was determined using pull-out test and stress values are correlated to fracture mechanisms based on SEM observations.


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