Temperature Self-Reference Gas Pressure Sensor Based on Intracavity Sensing of Fiber Ring Laser

The temperature cross-sensitivity is always challenging for the design and application of fiber-optic gas pressure sensors. Here, a temperature self-reference gas pressure sensor based on intracavity sensing of fiber ring laser has been demonstrated. The Fabry-Perot interferometer and fiber Bragg grating are cascaded as reflection sensing head and coupled into a fiber ring laser. The Fabry-Perot interferometer shows high sensitivities of gas pressure and temperature because of its specific fiber micro cavity structure. The fiber Bragg grating has narrow-band filtering characteristics at a certain wavelength, which ensures the desired accuracy for intracavity sensing, and has good temperature response characteristics. In the temperature self-reference sensing system, the output wavelength of the fiber ring laser is only modulated by the sensor temperature, while the output intensity is simultaneously modulated by the sensor temperature and gas pressure. The sensing model of the temperature self-reference gas pressure sensor has been presented. The experiment verifies that the scheme can measure gas pressure and temperature simultaneously. The stability and measurement errors have been analyzed. The proposed sensing system provides a potential solution for solving temperature cross-sensitivity in gas pressure measurement and can be extensible to similar fiber-optic sensors.