Fabrication and sensing characteristics of a fiber-optic air pressure sensor based on the Vernier effect
A high-sensitivity fiber-optic pressure sensor is demonstrated, based on the Vernier effect in a cascaded dual Fabry–Pérot interferometer. The sensor incorporates a 343 μm polarization-maintaining fiber and a single-mode fiber, precisely aligned and secured within a ceramic sleeve to form an air cavity. The Vernier effect is realized by precisely controlling the silica cavity length through a fiber polishing process, which significantly enhances the gas pressure sensitivity. The device exhibits a linearity of 99.68% and a sensitivity of 50.93 pm kPa−1 over the range of 50.2 kPa–201.8 kPa. Owing to its compact structure, robust fabrication, and good short-term stability, this sensor holds great potential for gas pressure monitoring applications.