Broadband Fiber-Optic Acoustic Sensors

• Published in: Journal of lightwave technology Vol. 40; no. 12; pp. 4033 - 4041
• Main Authors: Wei, Heming, Gong, Zhe, Wu, Wenjing, Che, Jiawei, Zhang, Liang, Pang, Fufei, Wang, Tingyun
• Format: Journal Article
• Language: English
• Published: New York IEEE 15-06-2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic emission; Acoustic sensor; Acoustic waves; Bragg gratings; Broadband; Doped fibers; Erbium; Erbium-doped fiber lasers; fiber Bragg grating; Fiber gratings; Fiber lasers; fiber optic sensor; Fiber optics; fiber ring laser; Laser outputs; Mach-Zehnder interferometers; Optical fiber couplers; Optical fiber sensors; Optical interferometry; Ring lasers; Sensitivity; Sensors; unbalanced Mach-Zehnder interferometer
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2022.3154724

A broadband fiber-optic acoustic sensing system is proposed and demonstrated, which is configured by a fiber Bragg grating (FBG) and an erbium-doped fiber (EDF) ring laser. As the acoustic waves can shift the FBG reflective spectrum, the wavelength of the laser output shifts accordingly and this shift is subsequently converted into a corresponding phase shift and demodulated by an unbalanced fiber-optic Mach-Zehnder interferometer (MZI). The sensitivity of the presented sensing system is also investigated, which is a function of the optical path difference of the MZI and the linewidth of the FBG. Due to the adaptability and high sensitivity of the system, it can detect signals with frequencies from tens of hertz to hundreds of kilohertz, which shows the potential for acoustic emission detection in real applications.