Highly Sensitive Optical Fiber Fabry–Perot Gas Pressure Sensor Based on Microwave Photonics With Phase Demodulation

This article expounds a highly sensitive Fabry-Perot interferometer (FPI) gas pressure sensor that employs microwave photonics with phase demodulation technique. This interrogation method, utilizing a similar configuration as the single passband microwave photonic filter demodulation method, leverages the system's phase response and exhibits notable sensitivity compared to tracking the shift of the central frequency within the filter passband. A highly sensitive FPI sensor with the sensitivity of 22.9238 rad/MPa and extremely high linearity of 0.99997 is achieved within the gas pressure range of 0-0.27 MPa. Additionally, the sensor demonstrates minimal sensitivity to temperature variations. Moreover, the sensitivity can be finely adjusted to strike an optimal balance between sensitivity and measurement range by utilizing different cavity lengths of the FPI.