Using a MEMS All-Quartz Fiber-Optic Fabry–Pérot High-Temperature Pressure Sensor Based on a Nanoforest Array to Enhance Interference Signals

This paper presents and experimentally demonstrates an all-quartz fiber-optic Fabry–Pérot (FP) high-temperature pressure sensor with interference signal enhancement based on micro-electro-mechanical system (MEMS) technology. By incorporating a nanoforest array and an optical microsphere lens, the quality of the optical interference signal generated by the multilayer fiber-optic FP sensing structure is effectively enhanced. MEMS fabrication and high-temperature bonding techniques are employed to enable batch fabrication of the sensing units, while laser fusion splicing is utilized to achieve adhesive-free packaging and integration of the sensor with high-temperature-resistant optical fibers. Experimental results demonstrate that the fabricated all-quartz fiber-optic FP high-temperature pressure sensor enables stable pressure measurements over a range of 0–200 kPa within a temperature range of 20–700 °C. At room temperature, the sensor exhibits a pressure sensitivity of 56.6 nm/kPa and a maximum nonlinearity error of 0.49% F.S. In addition, the sensor maintains good operational stability under high-temperature conditions. Owing to its all-quartz structure, the proposed sensor offers excellent high-temperature resistance, good temperature stability, and strong potential for batch fabrication, providing a viable approach for the development and application of fiber-optic pressure sensors in high-temperature environments.