Ultrasensitive Fiber Gas Pressure Sensor Based on Two Diaphragm Fabry-Perot Interferometers and Enhanced Vernier Effect

We propose a novel FPI sensing unit that can sense gas pressure through two parameters: the refractive index of the gas in the cavity and the geometric cavity length. This two parameter FPI is connected in parallel with a normal diaphragm-type FPI to achieve enhanced Vernier effect, resulting in a fiber gas pressure sensor with a high sensitivity of 74.33nm/KPa.