Development of highly sensitive fiber-optic acoustic sensor and its preliminary application for sound source localization

Abstract

A metal diaphragm-based omnidirectional fiber-optic acoustic sensor with high sensitivity has been developed in this work. The acousto-optic transducer of the sensor is a single-wavelength extrinsic Fabry–Pérot interferometer (EFPI) that is highly sensitive to the displacement of the diaphragm’s center. The sensor can stably work in the linear response region of the EFPI in a wide range of temperature from −20 to 60 °C. The pressure sensitivity of the sensor is larger than 800 mV/Pa, and the sensitivity fluctuation in the frequency range from 100 Hz to 6 kHz is smaller than 3 dB. The noise-limited minimum detectable pressure obtained at 1 kHz of the sensor is 126 μPa/Hz1/2. In addition, the above-prepared fiber-optic acoustic sensors present excellent phase consistency with each other, which facilitates the formation of a sensor array for sound source localization. In this work, a cross-shaped fiber-optic sensor array was prepared and then used to detect and track a small drone flying in the field. The experimental results show that the sensor array can capture the acoustic fingerprint of the drone at a distance as far as 300 m. This detection distance is more than ten times longer than that of a conventional electret condenser microphone. The azimuth angle of the drone obtained with the fiber-optic acoustic sensor array has a deviation of smaller than 10° relative to the GPS data from the drone.

Research on sound source localization of fiber optic FP cavity microphone based on TDOA

“…In the same year, Wang et al [8] proposed a fiber-optic acoustic sensor array based on Michelson interference, the positioning accuracy can reach 1 cm in 60 cm×60 cm. In 2020, Hayber et al [9] used polymer diaphragm materials to form an optic fiber sensor array and applied genetic algorithm to obtain the position coordination of the sound source with a maximum positioning error of 2.48 cm in 1 m×1 m×1 m. In 2021, Wu et al [10] developed a highly sensitive metal diaphragm omnidirectional fiber optic acoustic sensor and designed a cross shaped fiber optic sensor array that was capable of capturing acoustic fingerprints of drones within a 300 m range, achieving accurate recognition of drones over a wide range. In 2021, Xia et al [11] proposed a compact multi-point acoustic sensing array system that utilized laser modulated quasi continuous phase shift interferometry to achieve simultaneous demodulation of a diaphragm type fiber optic acoustic sensing array, with a positioning error no more than 1.98 cm.…”

A Grating Interferometric Acoustic Sensor Based on a Flexible Polymer Diaphragm

“…Optical interferometric acoustic sensors have been widely studied recently and have advanced applications in areas such as sound source localization [ 1 , 2 , 3 ], speaker recognition [ 4 ] and medical devices [ 5 , 6 ]. The most dominant acoustic sensors are based on the principle of capacitive detection.…”

A Flexible Piezoelectric Device for Frequency Sensing from PVDF/SWCNT Composite Fibers

“…Acoustic detectors are used in a wide range of fields, such as voice communication, environmental noise monitoring, flight tracking and detection, and photoacoustic spectroscopy [ 1 , 2 , 3 ]. In addition, many frequency-vibration sensors have been used over the years in various ways as accelerometers.…”