Miniature Structure Optimization of Small-Diameter FBG-Based One-Dimensional Optical Fiber Vibration Sensor

We proposed a miniature one-dimensional vibration sensor based on a small-diameter fiber Bragg grating in this paper. The working principle and theoretical model of the FBG vibration sensor were deduced and established theoretically. A genetic algorithm has been used to globally optimize the nonlinear programming problem of sensor size and sensitivity. The modal analysis of the vibration sensor was carried out by using finite element software to verify the feasibility of the optimization results. Then metal 3D printing was utilized to realize the integrated processing and miniaturization of the sensor. The experimental results show that the natural frequency of the sensor packaged with the small-diameter FBG is 1949.5Hz, and the sensor has a good working state in the frequency range of 5-1300Hz. The sensitivity and the linearity of the optimized sensor are 65.42 pm/g and 99.997% at the frequency of 100Hz, respectively. Through the comparative experiments, it can be found that the small-diameter FBG presents an obvious sensitization effect compared to the ordinary FBG with a 118.3% sensitivity improvement. This optimization theory is promising in multi-dimension, high performance, and microminiaturization optical vibration sensor design and fabrication.