Publication: Acousto-Optic Comb Interrogation System for Random Fiber Grating Sensors with Sub-nm Resolution
Loading...
Identifiers
Publication date
2021-06-08
Defense date
Advisors
Tutors
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Impact
Export
Abstract
The broad-frequency response and nanometer-range displacements of ultrasound detection are essential for the characterization of small cracks, structural health monitoring and non-destructive evaluation. Those perturbations are generated at sub-nano-strain to nano-strain levels. This corresponds to the sub-nm level and, therefore, to about 0.1% of wavelength change at 1550 nm, making it difficult to detect them by conventional interferometric techniques. In this paper, we propose a demodulation system to read the random fiber grating spectrum using a self-heterodyne acousto-optic frequency comb. The system uses a self-heterodyne approach to extract phase and amplitude modulated signals to detect surface acoustic waves with sub-nanometer amplitudes in the frequency domain. The method can detect acoustic frequencies of 1 MHz and the associated displacement. The system is calibrated via phase detection with a heterodyne interferometer, which has a limited frequency response of up to 200 kHz. The goal is to achieve sub-nanometer strain detection at MHz frequency with random fiber gratings.
Description
Keywords
Self-heterodyne comb, Random fiber grating, Fbg, Ultrasound
Bibliographic citation
Poiana, D. A., Garcia-Souto, J. A., & Bao, X. (2021). Acousto-Optic Comb Interrogation System for Random Fiber Grating Sensors with Sub-nm Resolution. Sensors, 21(12), 3967.