High sensitivity fiber-optic Michelson interferometric low-frequency acoustic sensor based on a gold diaphragm

Abstract

A Michelson interferometric fiber-optic acoustic sensor based on a large-area gold diaphragm is proposed in this paper. The Michelson interferometer (MI) based on 3×3 coupler is comprised of two beams that reflected from the gold diaphragm and a cleaved fiber end face. Thickness and diameter of the gold diaphragm are 300 nm and 2.5 mm, respectively. Based on the phase difference between each output port of the 3×3 fiber coupler, an ellipse fitting differential cross multiplication (EF-DCM) interrogation process is induced for phase demodulation, which can overcome the phase distortion caused by property degradation of 3×3 coupler. Experimental results show that the sensor has a phase sensitivity of about -130.6 dB re 1 rad/μPa@100 Hz. A flat response range between 0.8 to 250 Hz is realized with the sensitivity fluctuation below 0.7 dB. Besides, the signal-to-noise ratio (SNR) and minimal detectable pressure (MDP) of the sensor are 57.9 dB and 10.2 mPa/Hz1/2 at 5 Hz. The proposed sensor exhibits superiorities of compact size, high sensitivity, flat low-frequency response and ease of mass production, which gives the sensor great potential for low-frequency acoustic sensing and photo-acoustic spectroscopy.

Fast interrogation of dynamic low‐finesse Fabry‐Perot interferometers: A review

“…With the improvement of the algorithm, for the non‐quadrature phase shift, as long as the phase‐shift step is known (not an integer multiple of π), two orthogonal signals can be constructed to extract phase information 32 . Corresponding phase can be calculated by: The phase‐shift step β and the DC value A can be estimated by full‐spectrum analysis or by ellipse fitting of Lissajous figures between the two detected signals 33 . In this case, the A is regarded as a constant.…”

High Sensitivity and High Stability Dual Fabry-Perot Interferometric Fiber-Optic Acoustic Sensor Based on Sandwich-Structure Composite Diaphragm

“…Diaphragm-based fiber optic acoustic sensors have attracted much interest because of their high sensitivity [8]- [10], wide frequency band [11]- [13], and high dynamic range [14]. Several diaphragms have been used to detect acoustics waves, such as metal (silver [8], [15], gold [16], [17]), two dimension materials (graphene oxide [11]), graphene [12], [13], silicon nitride [18], [19], and polymer (PPESK [20], PET [21]- [23]). Other than metal diaphragm, the rest diaphragms face the problem of low reflectivity.…”

Acoustic Optical Fiber Sensor Based on Graphene Oxide Membrane

“…Optical fiber sensors for acoustic waves detection is based in different mechanisms including photoacoustics [13], with special interest in the biomedical field [14,15], interferometry [16,17], among other [18][19][20]. In particular, interferometry-based sensors have found many research interests due to the compact size and simple fabrication.…”