A Multi-Groove Ceramic-Packaged Sapphire-Diaphragm Fiber Sensor for High-Temperature Vibration

A sapphire-diaphragm fiber-optic vibration sensor for high-temperature applications is proposed and experimentally demonstrated. Its sensing unit consists solely of a monolithic sapphire sensitive diaphragm encapsulated in a multi-groove ceramic housing, forming a stable Fabry-Pérot interferometer. Experimental shows that the sensor achieves reliable vibration measurements up to 10 g across a temperature range of 17°C to 800°C, with a room-temperature sensitivity of 5.18 nm/g and a resonant frequency of 9.65 kHz. After being subjected to a 237 g impact at room temperature, the amplitude–frequency response error within the 20-3000 Hz band remains approximately 6.2%. Experimental results demonstrate that the sensor features a compact structure and robust performance, offering a reliable solution for vibration monitoring in harsh environments.