Theoretical Model and Design of Highly Sensitive Reflective Fiber Optic Fabry-Pérot Cavity Accelerometer Independent of Fiber Stiffness

The sensitivity of accelerometer based on fiber Bragg grating (FBG) is limited by the stiffness of the encapsulated fiber, and this paper is inspired to research the highly sensitive accelerometer of the Fabry-Pérot (F-P) cavity with wavelength demodulation which is not affected by fiber stiffness. The mechanism of a new type sensor based on the F-P cavity is researched, and the constraints of sensitivity and resonant frequency are researched systematically. The figure of merit is introduced to evaluate the comprehensive performance of the accelerometer. Theoretical analysis indicates that F-P cavity accelerometer does have a good advantage, its sensitivity is two orders of magnitude higher than that of the FBG accelerometer. The experimental results show that a bandwidth of the sensor ranges from 10 Hz to 350 Hz, a corresponding sensitivity range is from 5.95 nm/G to 10.12 nm/G, and the figure of merit is 6278.4 nm·Hz/G. Thus it can be sufficiently demonstrated that the model has the potential advantages of ultra-high sensitivity and miniaturization, which has potential theoretical significance and practical application value in the field of vibration signal detection.