Highly Sensitive Gas Pressure Sensor Based on Fabry-Perot Interferometers and the Vernier Effect
A highly sensitive gas pressure sensor based on the Vernier effect (VE) and Fabry-Perot interferometers (FPIs) has been proposed. The sensing structure was fabricated by fusion-splicing a single-mode fiber (SMF) with two quartz-capillary sections of different inner diameters, followed by coating a polydimethylsiloxane (PDMS) film on the end face of the terminal capillary. The experimental results show that the pressure sensitivities during the pressurization and depressurization processes were -431.4908 and -363.1582 nm/MPa,with linear fitting coefficients of 0.9902 and 0.9758, respectively. The difference between the two sensitivities is mainly attributed to the viscoelastic hysteresis of the PDMS film, delayed stress relaxation, incomplete elastic recovery, and experimental uncertainty. The results indicate that the proposed sensor has the advantages of compact size, relatively simple fabrication, high sensitivity, and favorable linear response, suggesting its potential for slight-pressure monitoring and pressure detection in confined spaces.