A wide-band, high-sensitivity acoustic sensor with multi-thin-film packaged waveguide-coupled resonant cavity structure

Abstract

The invention relates to an acoustic sensor, in particular to anacoustic sensor with multi-film encapsulated waveguide coupled resonator structure. The acoustic sensor comprises a closed cavity, multifilms placed directly above the closed cavity, and a straight waveguide and a ring resonator located inside the closed cavity. The multi films are used to isolate external environment, conduct a sound wave, and form the closed cavity, so that the sound wave cause a change in gas volume in the closed cavity, thereby causing the change in gas density, furthermore, causing the change in gas refractive index in the cavity. The gas in the closed cavity exists as a cladding of the waveguide coupled resonator structure. The resonant frequency of the waveguide coupled resonator will drift to detect the external sound wave when the cladding density changes. Due to the use of the waveguide-coupled cavity structure, the sensor uses the change of gas medium refractive index totallyreflected in the acoustic wave cavity as adetection principle. The sound detection band is wide and sensitivity is high, so that the sensor is suitable for fieldof detection of a underwater acoustic signal, process control in industrial environment, medical diagnostics and the like.

Description

technical field [0001] The invention relates to an acoustic sensor, in particular to a wide-band, high-sensitivity acoustic sensor with a multi-film packaged waveguide coupling resonant cavity structure. Background technique [0002] Acoustic sensors are sensors that sense sound waves and convert them into usable output signals. Traditional acoustic sensors mainly use thin film or piezoelectric materials as sensitive structures, and collect acoustic signals through mechanical vibration. This acoustic sensor is affected by moving parts, and the frequency band is only concentrated at the resonant frequency of the moving parts, making the frequency band of the sensor narrow. ; Based on the detection principle of movable parts, the intrinsic detection sensitivity is not high, and the traditional structure is also susceptible to the influence of the external environment and easily produces serious noise, the signal-to-noise ratio is low, and the sensitivity of the sensor is low. ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a wide-band, high-sensitivity acoustic sensor with a multi-thin film packaged waveguide coupling resonant cavity structure in order to solve the problems of narrow frequency band and low sensitivity in the existing acoustic sensors

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