Analysis of the phase response of fiber Bragg gratings to longitudinal ultrasonic fiields in the high frequency regime: towards new interrogation strategies
ABSTRACT In this work the behaviour of a fiber Bragg grating (FBGs) phase response subjected to longitudinal ultrasonic (US) field has been investigated. Numerical results reveal high sensitivity of the FBG phase response and thus of the time delay to US waves in the high frequency and low amplitude regime. The potentialities to extend the sensing capability of FBG sensors as high frequency ultrasonic detectors are discussed with regard to new interrogation strategies based on time delay measurements.
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ABSTRACT: This paper gives a review of acoustic and ultrasonic optical fiber sensors (OFSs). The review covers optical fiber sensing methods for detecting dynamic strain signals, including general sound and acoustic signals, high-frequency signals, i.e., ultrasonic/ultrasound, and other signals such as acoustic emissions, and impact induced dynamic strain. Several optical fiber sensing methods are included, in an attempted to summarize the majority of optical fiber sensing methods used to date. The OFS include single fiber sensors and optical fiber devices, fiber-optic interferometers, and fiber Bragg gratings (FBGs). The single fiber and fiber device sensors include optical fiber couplers, microbend sensors, refraction-based sensors, and other extrinsic intensity sensors. The optical fiber interferometers include Michelson, Mach-Zehnder, Fabry-Perot, Sagnac interferometers, as well as polarization and model interference. The specific applications addressed in this review include optical fiber hydrophones, biomedical sensors, and sensors for nondestructive evaluation and structural health monitoring. Future directions are outlined and proposed for acousto-ultrasonic OFS.IEEE Sensors Journal 08/2008; · 1.48 Impact Factor