An Optical Fiber Cantilever Beam Ultrasound Sensor Based on MI Structure

This article presents an optical fiber cantilever beam sensor based on a Michelson interferometer (MI) structure for ultrasound detection. Optimized structural parameters of the proposed sensor can be obtained according to simulated analysis of the effect of structural parameters on sensor’s ultrasound performance. The experimental parameters of the prepared sensor are measured, with a length of fiber cantilever beam (FCB) of 2405.34μm, a length of taper of 612.30μm, a diameter of taper of 26.80μm, and a diameter of silica sphere of 32.33μm. The maximum signal-to-noise ratio (SNR) is calculated as 29.8dB in the ultrasound response range of 20kHz to 509kHz. The sensor utilizes multiple modes interference based on SMF only structure, a single-taper and a reflective structure of a silica sphere, resulting in a more compact and structurally stable design compared to sensors based on a Mach-Zehnder interferometer (MZI) and a Fabry-Perot interferometer (FPI). The proposed MI-based FCB ultrasound sensor in this article offers advantages such as a compact structure, easy fabrication method, and a large measurement range.