The Fibre-Optic Gyro
The fibre-optic gyro or FOG is a state of the art commercial passive Sagnac interferometer made with several kilometers of optical fibre. While not as accurate or precise as our large ring lasers, this device is nevertheless useful for a variety of small experiments. Fibre optic gyros have been used in the past in collaboration with the department of civil engineering who study the response of buildings in earthquakes.
Ulli Schreiber using a FOG to demonstrate the measurement of the motion of the Auckland sky tower.
Motion of the Auckland sky tower measured with a FOG compared to conventional potentiometer measurements.