Stabilization of an embedded fiber optic Fabry-Perot sensor for ultrasound detection

Dorighi, John; Krishnaswamy, Sridhar; Achenbach, Jan Drewes

doi:10.1109/58.464837

Cited by 84 publications

(26 citation statements)

References 16 publications

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“…Thus they reluctantly reduced the number of sensors to sense the high frequency signals [7]. Another problem to be solved is that it was hard to maintain the sensitivity of the FBG ultrasonic sensors under the changing environments [8,9] because the physical properties of optical components such as Fabry-Perot filter can easily influenced by external perturbations. Therefore, for the efficient and stable impact monitoring system, it is necessary to develop the stabilization controlled FBG sensor system capable of multiplexing with wide dynamic range.…”

Section: Introductionmentioning

confidence: 99%

Impact monitoring in smart composites using stabilization-controlled FBG sensor system

et al. 2004

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Impact location monitoring is one of the major concerns of the smart health monitoring. For this application, multipoint ultrasonic sensors are to be employed. In this study, a multiplexed FBG sensor system with wide dynamic range was proposed and stabilization controlling system was also developed for the maintenance of maximum sensitivity of sensors. For the intensity demodulation system of FBG sensors, Fabry-Perot tunable filter (FP-TF) with 23.8 nm FSR (free spectral range) was used, which behaves as two separate filters between 1530 ~ 1560 nm range. Two FBG sensors were attached on the bottom side of the graphite/epoxy composite beam specimen, and low velocity impact tests were performed to detect the one-dimensional impact locations. Impact locations were calculated by the arrival time differences of the impact longitudinal waves acquired by the two FBGs. As a result, multiplexed in-line FBG sensors could detect the moment of impact precisely and found the impact locations with the average error of 1.32 mm.

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Section: Introductionmentioning

confidence: 99%

Impact monitoring in smart composites using stabilization-controlled FBG sensor system

et al. 2004

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“…12,13 Many interferometric sensors operate over the linear region of an interference fringe. 1,3,4,8,9,11 Compared with sensors that use fringe counting, 5,9,11 sensors that operate in the linear region have the advantages of a linear transfer function, no ambiguity in fringe direction, simple signal processing, and highest sensitivity at the quadrature point ͑Q point͒. They are, therefore, suitable for detection of small optical path differences ͑OPDs͒ and wideband applications.…”

Section: Introductionmentioning

confidence: 99%

Grating-assisted demodulation of interferometric optical sensors

Wang

2003

Appl. Opt.

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Accurate and dynamic control of the operating point of an interferometric optical sensor to produce the highest sensitivity is crucial in the demodulation of interferometric optical sensors to compensate for manufacturing errors and environmental perturbations. A grating-assisted operating-point tuning system has been designed that uses a diffraction grating and feedback control, functions as a tunablebandpass optical filter, and can be used as an effective demodulation subsystem in sensor systems based on optical interferometers that use broadband light sources. This demodulation method has no signaldetection bandwidth limit, a high tuning speed, a large tunable range, increased interference fringe contrast, and the potential for absolute optical-path-difference measurement. The achieved 40-nm tuning range, which is limited by the available source spectrum width, 400-nm͞s tuning speed, and a step resolution of 0.4 nm, is sufficient for most practical measurements. A significant improvement in signal-to-noise ratio in a fiber Fabry-Perot acoustic-wave sensor system proved that the expected fringe contrast and sensitivity increase.

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“…The photodiode detects both the low frequency intensity variations ( < 500 Hz) associated with sensor drift and the high frequency intensity variations (500kHz -10 MHz) related to ultrasound. The embedded fiberinterferometerwas maintained at its most sensitive operating point, quadrature, using an active homodyne stabilization technique which tuned the laser frequency to compensate for sensor drift [10].…”

Section: Methodsmentioning

confidence: 99%