Fibre-optic gyroscope

However its principle of operation is instead based on the interference of light which has passed through a coil of optical fibre, which can be as long as 5 kilometres (3 mi).

Beam splitting optics split light from a laser diode (or other laser light source) into two waves propagating in both clockwise and anticlockwise directions through a coil consisting of many turns of optical fibre.

[2] A FOG provides extremely precise rotational rate information, in part because of its lack of cross-axis sensitivity to vibration, acceleration, and shock.

Because of their intrinsic reliability and long lifetime, FOGs are used for high performance space applications [3] and military inertial navigation systems.

The FOG typically shows a higher resolution than a ring laser gyroscope.