A high-reliability acceleration sensor based on fiber Bragg grating (FBG) that can be used in downhole for a long time is proposed, which is aimed at solving the problem of low-reliability of existing optical fiber acceleration sensors in the field of petroleum and natural gas resources exploration. The acceleration sensor uses the inertial force generated by the mass to make the symmetrically tilting cantilever beams bend slightly to detect the vibration signal. Using solder glass to package FBG is an important method to ensure that the sensor maintains high stability in harsh environment. It can significantly reduce the creep and improve the thermal shock resistance of the sensor. Through theoretical calculation, the sensitivity formula of sensor is derived, and the size parameters that can maximize sensitivity is solved by MATLAB. After that, the performance of the sensor and the stability at high temperature are tested. Experiments show that the operating frequency range of the acceleration sensor is from 0.1 Hz to 30 Hz, the sensitivity is 290 pm/g at room temperature, and the maximum lateral interference degree is 3.6. Most importantly, the sensor packaged by glass welding can keep excellent stability under longterm high temperature. Moreover, the sensor has a quick response to severe temperature shock and can maintain measuring accuracy after cyclic thermal shocks. Therefore, the sensor can be reliably used for micro-vibration measurement in harsh environments such as downhole.
展开▼
