Highly Sensitive Temperature and Pressure Sensor Based on Fabry–Perot Interference

In this letter, we propose and experimentally demonstrate an optical fiber structure sensor using Fabry-Perot interference for temperature and pressure measurement. The sensor head consists of an incident single-mode fiber, a section of capillary pure silica tube, and refractive index matching fluid. The measurement of cavity length change with different pressure and temperature has been achieved by monitoring the wavelength shift of the interference pattern in the reflection spectra. For the change in a small scale, the measurement sensitivity of temperature is 6.95 nm/°C and the estimated sensitivity of pressure is 0.15 nm/Pa. The sensor has the advantages of high sensitivity, low cost, compact size, and flexibility.