Temperature-insensitive acceleration sensing technology based on π phase of double fiber Bragg gratings

A novel temperature-independent technology based on π phase of double fiber Bragg grating (FBG) acceleration is proposed. The double fiber Bragg grating accelerometer is designed. The temperature response and acceleration response of the sensor versus wavelength are researched. The configuration and coating of the accelerometer are designed. The temperature-independent principle based on π phase of double fiber Bragg grating accelerometer is analyzed. The temperature response of FBGs and the acceleration response versus wavelength are analyzed. And the analytical formula of acceleration sensitivity is also deduced. Acceleration response and flat range of the accelerometer are analyzed by experiment. Experimental results indicate that precise measurement can be realized in the large range of temperature, and the sensitivity is 15.52 pm/(m·s^-2), relative error is 3.06%. The sensor demonstrates extremely linear response, and linear fitting is 99.8%. There is a good flat response at frequencies less than the mechanical resonance frequency, which indicates that the accelerometer has good temperature-independent characteristic and can realize precise measurement.