A Temperature-Insensitive Closed Chamber Gas Pressure Detection Method Based on Double-Layer Fiber Bragg Grating

Real-time monitoring of gas pressure inside a sealed gas chamber is a crucial aspect of the gas sensing field. To address the issue of cross-sensitivity between stress and temperature in fiber optic gas pressure sensors and achieve precise and linear measurement of gas pressure, this research proposes a detection method based on a double-layer fiber Bragg grating (FBG) string. This method enables accurate detection of changes in gas pressure within a closed chamber without temperature interference. To mitigate the issue of stress and temperature crosstalk, a pair of FBGs are vertically connected in series using a double-layer design approach. In addition, the sensor's performance parameters can be determined through the use of control variates. Experimental results demonstrate that within the range of 100-300 kPa, the gas pressure sensitivity is 6.1 pm/kPa. The gas pressure detection error rate falls within the range of 0%-1.81%, and the sensitivity to temperature is 0.01 pm/degrees C, manifesting minimal impact from temperature variations. Furthermore, the sensor exhibits excellent repeatability and reproducibility, making it highly promising for a wide range of applications.