Fiber optic sensors for health monitoring of morphing airframes: II. Chemical sensing using optical fibers with Bragg gratings

2000 ◽  
Vol 9 (2) ◽  
pp. 170-174 ◽  
Author(s):  
Karen Wood ◽  
Timothy Brown ◽  
Robert Rogowski ◽  
Brian Jensen
Keyword(s):  
Optical Fibers ◽  
Health Monitoring ◽  
Chemical Sensing ◽  
Fiber Optic ◽  
Bragg Gratings ◽  
Fiber Optic Sensors

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.

scholarly journals CRYOGENIC FIBER OPTIC SENSORS BASED ON FIBER BRAGG GRATINGS

2008 ◽  
Author(s):  
P. R. Swinehart ◽  
M. Maklad ◽  
S. S. Courts ◽  
J. G. Weisend ◽  
John Barclay ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Fiber Optic Sensors

FIBER OPTIC SENSORS IN STRUCTURAL HEALTH MONITORING

2009 ◽  
pp. 378-402
Author(s):  
Maurizio Giordano ◽  
Jehad Sharawi Nasser ◽  
Mauro Zarrelli ◽  
Andrea Cusano ◽  
Antonello Cutolo
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Structural Health

scholarly journals Fiber Bragg grating fabrication by femtosecond laser radiation

2019 ◽  
Vol 220 ◽  
pp. 03007
Author(s):  
Anton Chernikov ◽  
Dmitriy Kochuev ◽  
Kirill Khorkov ◽  
Ruslan Chkalov ◽  
Nikolay Davydov
Keyword(s):  
Laser Radiation ◽  
Femtosecond Laser ◽  
Fiber Bragg Grating ◽  
Fiber Optic ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Fiber Optic Sensors ◽  
Bragg Grating ◽  
Femtosecond Laser Radiation ◽  
Grating Fabrication

The paper presents the results of fiber Bragg gratings fabrication by femtosecond laser radiation using point-by-point and line-by-line inscription methods. The approach makes it possible to fabricate the second and higher diffraction orders fiber Bragg gratings, which can be used as sensitive elements of fiber-optic sensors.

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