Fiber-optic Fabry–Pérot interferometric accelerometer with composite cavity and temperature calibration for high-temperature and high-pressure applications

Abstract To address the demand for flow-induced vibration monitoring of steam generator heat transfer tubes in pressurized water reactors under high-temperature (350 °C) and high-pressure (17.5 MPa) conditions, a fiber-optic Fabry–Pérot interferometric accelerometer based on a composite Fabry–Pérot cavity structure is proposed. The sensor employs a symmetrically arranged multidirectional cantilever beam and a central proof mass to effectively reduce cross-axis sensitivity. Using a MEMS-based fab