High-fineness fiber-optic Fabry–Perot vibration sensor based on silicon MEMS technology

In this work, a high-fineness MEMS-based fiber-optic Fabry–Perot vibration sensor is proposed and designed. The sensor is assembled using a fiber-optic collimator, which significantly simplifies the packaging and assembly procedure. The sensing element incorporates a BF33-Si-BF33 triple-layer wafer structure fabricated through deep reactive ion etching (DRIE) and anodic bonding. High-reflectivity optical films are deposited on the reflective surfaces of the F–P cavity to generate a high-fineness interference spectrum. The cavity length varies with external vibrations, causing a trough drift in the interference spectrum. The drifted spectrum is directly demodulated using a high-speed commercial optical interrogator. Experimental results show that the flat frequency range is from 10 to 2500 Hz, with the average spectrum sensitivity of 197 pm/g and the acceleration resolution of 5.24 mg, complemented by excellent linearity and low transverse sensitivity. The sensor features high acceleration resolution and a broad flat frequency range, making it suitable for various applications.