Double F-P interference optical fiber Temperature and gas pressure sensor based on hollow core Bragg fiber.

A dual Fabry-Perot interferometric (FPI) temperature-gas pressure dual parametric sensor based on a hollow core Bragg fiber (HCBF) is introduced and validated experimentally for gas pressure monitoring in high-temperature settings. This dual parametric sensor employs a single mode fiber-hollow core Bragg fiber-single mode fiber (SMF-HCBF-SMF) structure to form a dual FPI, while the gas flow channel of the HCBF were processed by Femtosecond laser to make the sensor sensitive to gas pressure. Additionally, a novel white light interference demodulation technique is developed to demodulate the dual parametric sensor. Experimental findings corroborate theoretical predictions, the pressure measurement range of the proposed sensor reaches 0~10 MPa, the temperature measurement reaches 600°C. Pressure sensitivity greater than 50 nm/MPa over the full temperature rang. The high temperature and high sensitivity resistance of the proposed sensor highlights its potential for monitoring gas pressure in extreme high temperature environments.