Abstract
A flywheel-like sensitive diaphragm, which breaks the sensitivity limitations imposed by the increased thickness and the decreased radius in edge-clamped circular structure, has been proposed and analyzed in fiber Fabry-Perot (FP) acoustic sensor. A new model is built around the effect of diaphragm's structure parameters on sensitivity of a fiber FP acoustic sensor with common ductile material. The proposed sensor based on flywheel-like stainless diaphragm in 5mm diameter and 0.035mm thickness has been fabricated and its acoustic performances were tested. The test results show that our acoustic sensor can realize acoustic measurement from 0.1 kHz to 19 kHz. The sensor exhibits an acoustic pressure sensitivity of 1.525nm/Pa at the frequency of 4.5 kHz. The noise-limited minimum detectable pressure (MDP) level of ~13.06μPa/√Hz@4.5kHz and the acoustic pressure signal-to-noise ratio (SNR) of 70.42dB@4.5kHz are achieved, respectively. And the mean SNR of cavity length variation of 62.43dB can be acquired over the entire frequency range. Comparing with the edge-clamped circular structure, the flywheel-like structure endows the common ductile sheet material the ability to response to acoustic pressure. Cost-effective and compact size give the proposed acoustic sensor a competitive edge, something of crucial importance to commercial applications.
Highlights
Fiber optic acoustic sensor has shown its great potential in recent decades [1]–[12] because of their unique advantages such as immunity to electromagnetic interference, high resolution, fast response, and compact size
Various kinds of diaphragm materials have been studied for FPI acoustic sensors, such as silicon [3], silica [4], chitosan [5], silk fibroin [6], UV adhesive [7], silver [8], graphene [9], The associate editor coordinating the review of this manuscript and approving it for publication was Sukhdev Roy
Ni et al demonstrated a FPI acoustic sensor based on an ultrathin graphene diaphragm with a thickness of 10nm, and the noise-limited minimum
Summary
Fiber optic acoustic sensor has shown its great potential in recent decades [1]–[12] because of their unique advantages such as immunity to electromagnetic interference, high resolution, fast response, and compact size. A flywheel diaphragm fabricated by a structure parameters combination [4, 2, 0.5, 0.035] (in mm) (corresponding to CR’s inner diameter 2a, CD’s diameter 2r, spoke’s width w, and diaphragm’s thickness h) has been used to assemble the fiber FP acoustic sensor. In this case, a theoretical natural frequency of the proposed sensor is 7.975 kHz. And the diaphragm’s theoretical response curve simulated by ANSYS soft is shown in the Fig. (b). (2) ∼ (5) reveal that the acoustic pressure response sensitivity Sa(ω, t) of the proposed sensor is closely related to the structure parameters of a flywheel-like diaphragm The Eqs. (2) ∼ (5) reveal that the acoustic pressure response sensitivity Sa(ω, t) of the proposed sensor is closely related to the structure parameters of a flywheel-like diaphragm
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