Fiber grating sensors
TL;DR: In this paper, the authors review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings and intragrating sensing concepts.
Abstract: We review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings, intragrating sensing concepts, long period-based grating sensors, fiber grating laser-based systems, and interferometric sensor systems based on grating reflectors.
Citations
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TL;DR: This article reviews the recent progress in optical biosensors that use the label-free detection protocol, in which biomolecules are unlabeled or unmodified, and are detected in their natural forms, and focuses on the optical biosENSors that utilize the refractive index change as the sensing transduction signal.
2,060 citations
TL;DR: Among the various fiber-optic sensor technologies, especially, technologies such as fiber grating sensors, fiber- Optic gyroscopes, and fiber-Optic current sensors are discussed with emphasis on the principles and current status.
1,610 citations
TL;DR: In this paper, the authors reviewed recent research on fiber optic long-period gratings (LPGs) with emphasis placed upon the characteristics of LPGs that make them attractive for applications in sensing strain, temperature, bend radius and external index of refraction.
Abstract: Recent research on fibre optic long-period gratings (LPGs) is reviewed with emphasis placed upon the characteristics of LPGs that make them attractive for applications in sensing strain, temperature, bend radius and external index of refraction. The prospect of the development of multi-parameter sensors, capable of simultaneously monitoring a number of these measurands will be discussed.
1,203 citations
TL;DR: The recent research and development activities in structural health monitoring using FBG sensors have been critically reviewed, highlighting the areas where further work is needed.
Abstract: In-service structural health monitoring (SHM) of engineering structures has assumed a significant role in assessing their safety and integrity. Fibre Bragg grating (FBG) sensors have emerged as a reliable, in situ, non-destructive tool for monitoring, diagnostics and control in civil structures. The versatility of FBG sensors represents a key advantage over other technologies in the structural sensing field. In this article, the recent research and development activities in structural health monitoring using FBG sensors have been critically reviewed, highlighting the areas where further work is needed. A few packaging schemes for FBG strain sensors are also discussed. Finally a few limitations and market barriers associated with the use of these sensors have been addressed.
858 citations
TL;DR: In this paper, the authors present an overview of current research and development in the field of structural health monitoring with civil engineering applications, including building, piles, bridges, pipelines, tunnels, and dams.
838 citations
Additional excerpts
...Wavelength changes can be detected by an interrogator, which employs edge filters, tunable narrowband filters, or CCD spectrometers [27,28]....
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...Other approaches include the two-collocated-FBG method [27], which is based on the wavelength dependence of the strain-optic and thermo-optic effects....
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...[27]....
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References
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TL;DR: In this paper, the observation of photosensitivity in Ge-doped core optical fibers is reported. The photosensitivity is manifested by light-induced refractive index changes in the core of the waveguide.
Abstract: The observation of photosensitivity in Ge‐doped core optical fibers is reported. The photosensitivity is manifested by light‐induced refractive‐index changes in the core of the waveguide. Narrowband reflectors in a guide structure have been fabricated using this photosensitivity and the resulting DFB reflectors employed as laser mirrors in a cw gas laser in the visible.
2,294 citations
"Fiber grating sensors" refers background in this paper
...Gratings are simple, intrinsic sensing elements which can be photo-inscribed into a silica fiber [1]–[6] and have all the advantages normally attributed to fiber sensors....
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TL;DR: Bragg gratings have been produced in germanosilicate optical fibers by exposing the core, through the side of the cladding, to a coherent UV two-beam interference pattern with a wavelength selected to lie in the oxygen-vacancy defect band of germania, near 244 nm.
Abstract: Bragg gratings have been produced in germanosilicate optical fibers by exposing the core, through the side of the cladding, to a coherent UV two-beam interference pattern with a wavelength selected to lie in the oxygen-vacancy defect band of germania, near 244 nm. Fractional index perturbations of approximately 3 x 10(-5) have been written in a 4.4-mm length of the core with a 5-min exposure. The Bragg filters formed by this new technique had reflectivities of 50-55% and spectral widths, at half-maximum, of 42 GHz.
1,987 citations
01 Jan 1996
TL;DR: In this paper, a new class of long-period fiber gratings that can be used as in-fiber, low-loss, band-rejection filters is presented.
Abstract: We present a new class of long-period fiber gratings that can be used as in-fiber, low-loss, band-rejection filters. Photoinduced periodic structures written in the core of standard communication-grade fibers couple light from the fundamental guided mode to forward propagating cladding modes and act as spectrally selective loss elements with insertion losses act as backreflections <-80 dB, polarization-mode-dispersions <0.01 ps and polarization-dependent-losses <0.02 dB.
1,772 citations
TL;DR: In this paper, a new class of long-period fiber gratings that can be used as in-fiber, low-loss, band-rejection filters is presented.
Abstract: We present a new class of long-period fiber gratings that can be used as in-fiber, low-loss, band-rejection filters. Photoinduced periodic structures written in the core of standard communication-grade fibers couple light from the fundamental guided mode to forward propagating cladding modes and act as spectrally selective loss elements with insertion losses act as backreflections <-80 dB, polarization-mode-dispersions <0.01 ps and polarization-dependent-losses <0.02 dB.
1,696 citations
TL;DR: A novel class of highly sensitive sensors based on long-period fiber gratings that can be implemented with simple and inexpensive demodulation schemes are presented.
Abstract: We present a novel class of highly sensitive sensors based on long-period fiber gratings that can be implemented with simple and inexpensive demodulation schemes. Temperature, strain, and refractive-index resolutions of 0.65 °C, 65.75 μ∈, and 7.69 × 10−5, respectively, are demonstrated for gratings fabricated in standard telecommunication fibers.
1,267 citations