Fiber-optic seismometer on the basis of Mach-Zehnder interferometer

The seismometer based on fiber-optic Mach-Zehnder interferometer is proposed and tested. The sensing element of the seismometer is implemented as a multiturn optical fiber coil which allowed to obtain high responsivity to acceleration 6.1 × 103 V/g in the frequency range 1-20 Hz. Stability of the seismometer operation is provided by feed-back control of the interferometer working point. It is experimentally demonstrated that seismometer is able to reliably detect seismic vibration with acceleration amplitude at the level of 10−8g. Possibility of further increase of seismometer sensitivity is discussed.