Batch-producible MEMS fiber-optic Fabry–Perot pressure sensor for high-temperature application

Abstract

A fiber-optic Fabry-Perot pressure sensor based on a micro-electro-mechanical system (MEMS) and CO₂ laser fusion technology is developed and experimentally demonstrated for high-temperature application. The sensing heads are batch-fabricated by anodically bonding the micromachined Pyrex glass wafer and local gold-plated silicon wafer. The separated sensing head and the single-mode fiber are fused together to form the Fabry-Perot cavity using the CO₂ laser. In order to improve the measurement accuracy in a high-temperature environment, a fiber Bragg grating is used as a temperature sensor for temperature decoupling. The experimental results show that the fiber-optic Fabry-Perot pressure sensor has a maximum nonlinearity of 0.4%. The maximal error of the pressure after temperature decoupling is less than 1.05% over a pressure range of 0-0.5 MPa and a temperature range of 20°C-350°C. The batch fabrication technology makes the sensors low cost and high uniformity.