A fiber-optic sensor for the ground vibration detection

This study presents a fiber-optic sensor that senses ground vibrations generated by impact of rocks upon the ground. The vibration sensor of fiber-optic interferometer consists of an amplified spontaneous emission (ASE) light source, isolator, coupler, polarization controller, vibration-sensitized fiber-optic coil, and photo detector. Both laboratory experiments and field tests were carried out to compare ground vibration signals detected simultaneously by the fiber-optic sensor and a geophone. Experimental data indicates that ground vibration signals detected by the fiber-optic sensor is similar to that detected by the traditional geophone in the frequency spectrum ranges from 10 to 250Hz. Results of this study thus demonstrate the feasibility of this fiber-optic sensor for sensing ground vibrations produced by rock motions or other natural hazards.