Open AccessHigh sensitivity fiber-optic Michelson interferometric low-frequency acoustic sensor based on a gold diaphragm
Author(s) -
Pingjie Fan,
Wei Yan,
Ping Lü,
Wanjin Zhang,
Wei Zhang,
Xin Fu,
Jiangshan Zhang
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.402099
Subject(s) - optics , materials science , diaphragm (acoustics) , fiber optic sensor , interferometry , sensitivity (control systems) , optical fiber , michelson interferometer , demodulation , vibration , acoustics , physics , telecommunications , channel (broadcasting) , electronic engineering , computer science , engineering
A Michelson interferometric fiber-optic acoustic sensor based on a large-area gold diaphragm is proposed in this paper. The Michelson interferometer (MI) based on 3×3 coupler is comprised of two beams that reflected from the gold diaphragm and a cleaved fiber end face. Thickness and diameter of the gold diaphragm are 300 nm and 2.5 mm, respectively. Based on the phase difference between each output port of the 3×3 fiber coupler, an ellipse fitting differential cross multiplication (EF-DCM) interrogation process is induced for phase demodulation, which can overcome the phase distortion caused by property degradation of 3×3 coupler. Experimental results show that the sensor has a phase sensitivity of about -130.6 dB re 1 rad/μPa@100 Hz. A flat response range between 0.8 to 250 Hz is realized with the sensitivity fluctuation below 0.7 dB. Besides, the signal-to-noise ratio (SNR) and minimal detectable pressure (MDP) of the sensor are 57.9 dB and 10.2 mPa/Hz 1/2 at 5 Hz. The proposed sensor exhibits superiorities of compact size, high sensitivity, flat low-frequency response and ease of mass production, which gives the sensor great potential for low-frequency acoustic sensing and photo-acoustic spectroscopy.