Highly Sensitive Fibre Bragg Grating Geophone for Low-Frequency Seismic Detection

A highly sensitive fibre Bragg grating (FBG) geophone with temperature insensitivity has been developed for low-frequency seismic detection. This geophone utilizes a rubber-based diaphragm combined with a differential FBG technique to enhance vibrational sensitivity and eliminate temperature effects. This innovative method achieves a high vibrational sensitivity of 169.71 pm/g across a frequency range of 1 to 36 Hz while a low temperature sensitivity of 1.21 pm/°C is obtained over the range of 10 °C to 40 °C. Frequency spectrum comparisons demonstrate that the FBG geophone performs comparably to conventional electrical geophones.