TY - JOUR
T1 - Stabilization of an Embedded Fiber Optic Fabry-Perot Sensor for Ultrasound Detection
AU - Dorighi, John F.
AU - Krishnaswamy, Sridhar
AU - Achenbach, Jan D.
N1 - Funding Information:
Manuscript received December 15, 1994; revised March 7, 1995. This work was supported by the Air Force Office of Sponsored Research under Award F4960-92-J-0342AFOSR. The authors are with the Center for Quality Engineering and Failure Prevention, Northwestern University, Evanston, IL 60208 USA. IEEE Log Number 9413784.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 1995/9
Y1 - 1995/9
N2 - A method is proposed to stabilize an intrinsic fiber optic Fabry–Perot interferometric sensor embedded in a solid material for the purpose of detecting ultrasound. Without stabilization the interferometer drifts out of quadrature due to the presence of low-frequency dynamic strains. Stabilization is achieved by using active homodyne stabilization which tunes the laser frequency to maintain quadrature. A control loop shifts the laser frequency by 10 GHz at rates less than 25 Hz in order to compensate for induced drifts. The stabilization procedure was tested for a sensor embedded in an epoxy plate. Ultrasonic pulses, generated by a 5 MHz piezoelectric transducer, were detected with the embedded fiber sensor stabilized in the presence of applied low frequency strains. Improvements in sensitivity which result from stabilization are demonstrated. Additionally, a simulated acoustic emission signal, generated by a lead pencil break (Hsu-Neilson source), was detected with the sensor stabilized in the presence of dynamic strains.
AB - A method is proposed to stabilize an intrinsic fiber optic Fabry–Perot interferometric sensor embedded in a solid material for the purpose of detecting ultrasound. Without stabilization the interferometer drifts out of quadrature due to the presence of low-frequency dynamic strains. Stabilization is achieved by using active homodyne stabilization which tunes the laser frequency to maintain quadrature. A control loop shifts the laser frequency by 10 GHz at rates less than 25 Hz in order to compensate for induced drifts. The stabilization procedure was tested for a sensor embedded in an epoxy plate. Ultrasonic pulses, generated by a 5 MHz piezoelectric transducer, were detected with the embedded fiber sensor stabilized in the presence of applied low frequency strains. Improvements in sensitivity which result from stabilization are demonstrated. Additionally, a simulated acoustic emission signal, generated by a lead pencil break (Hsu-Neilson source), was detected with the sensor stabilized in the presence of dynamic strains.
UR - http://www.scopus.com/inward/record.url?scp=0029375578&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029375578&partnerID=8YFLogxK
U2 - 10.1109/58.464837
DO - 10.1109/58.464837
M3 - Article
AN - SCOPUS:0029375578
VL - 42
SP - 820
EP - 824
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
SN - 0885-3010
IS - 5
ER -