FBG seismometer optimized by genetic algorithm to realize 3-axis vibration detection using one fiber without bending

Abstract

We propose a 3-axis FBG seismometer in which the X- and Y-axis hinge structures are optimized and designed by genetic algorithm to precisely modulate their sensitivity and resonant frequency, thence possess basically the same vibration characteristics with the pre-fabricated spring structure that responsible for Z-axis vibration detection. Sensors on three axes operate in a frequency band of 20-90 Hz, the sensitivities of the proposed accelerometer in X,Y and Z directions are 401.088 pm/g, 413.580 pm/g and 402.075 pm/g respectively. Such application of algorithm enables our seismometer to realize quasi-distributed 3-dimensional vibration detection using one single fiber without bending, which will significantly reduce the diameter of the seismometer, eliminate the bending loss and broaden its application scenario.