Open AccessMicromachined extrinsic Fabry-Pérot cavity for low-frequency acoustic wave sensing
Author(s) -
Xin Fu,
Ping Lü,
Jin Zhang,
Zhiyuan Qu,
Wanjin Zhang,
Yujian Li,
Peng Hu,
Wei Yan,
Wenjun Ni,
Deming Liu,
Jiangshan Zhang
Publication year - 2019
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.024300
Subject(s) - fabry–pérot interferometer , materials science , optics , ferrule , interferometry , surface micromachining , pressure sensor , frequency response , sensitivity (control systems) , low frequency , optoelectronics , optical fiber , acoustics , wavelength , electronic engineering , fabrication , medicine , physics , alternative medicine , electrical engineering , pathology , thermodynamics , engineering , astronomy
In this work we demonstrate a low-frequency acoustic sensor structure based on extrinsic Fabry-Pérot interferometer (EFPI) cavity. The cavity is fabricated through micromachining techniques in a square silicon substrate with 4 mm side length and 400 μm thickness, which gives the sensor relative compact size. In the assembling process of the lead-in fiber, a D-shaped ceramic ferrule is designed to achieve the open cavity structure, which can balance the environmental pressure inside and outside the cavity and thus giving the sensor potentials of resisting strong pressure variations in some harsh application environments. Experimentally, sensor response to low-frequency acoustic waves from 0.1 Hz to 250 Hz is measured and demonstrated. A flat response region between 0.5 Hz to 250 Hz with sensitivity fluctuation of 0.8 dB is realized. Pressure resistant test of 25 MPa is also conducted on the sensor and exhibited to prove the function of the open cavity structure.