Fiber-optic ultrasound sensor with low reverberating noises

Fabry-Pérot (FP) based ultrasound sensors at fiber tips performed high sensitivity, broad bandwidth, and immunity of electromagnetic interference with relatively compact size. Nevertheless, the traditional FP-based optical fiber sensor has strong reverberation due to the high-quality factor of silicon. The reverberation at fiber tips causes strong noise that degrades the sensing capability. In this work, three design approaches were proposed accordingly to reduce the reverberation, including designs with eccentric-core, absorptive shield, and arc-edge. The simulation and experimental results showed that these approaches reduced the reverberation effectively. In brief, this research provided a low noise design for fiber-optic ultrasound sensing, paving the way to low-noise optical ultrasound sensing.