UV Adhesive Diaphragm-Based FPI Sensor for Very-Low-Frequency Acoustic Sensing

In this paper, we propose and demonstrate a fiber-optic extrinsic Fabry-Pérot interferometer (FPI) sensor based on an ultraviolet (UV) adhesive diaphragm for very-low-frequency acoustic sensing. The sensing diaphragm is formed by the surface tension of UV adhesive solution and exhibits a good acoustic response from 1 Hz to 20 kHz. The sensor has a sensitivity of 57.3 mV/Pa at 1000 Hz and a flat frequency response ranging from 1 to 2000 Hz with a small fluctuation of about ±1.5 dB. The good response of infrasound and rather simple fabrication process make it a wonderful candidate for very-low-frequency acoustic sensing.