Stabilization of an Embedded Fiber Optic Fabry-Perot Sensor for Ultrasound Detection

John F. Dorighi, Sridhar Krishnaswamy, Jan D. Achenbach

Research output: Contribution to journalArticlepeer-review

79 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)820-824
Number of pages5
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Volume42
Issue number5
DOIs
StatePublished - Sep 1995

ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering

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