Optical gyrometers

Experience and theory show that the observation of optical phenomena enables absolute rotations to be measured. This possibility, known since 1913, has recently been put into practice with the development of optical gyrometers.

Their operating principle involves important chapters of theoretical physics: quantum mechanics for the laser phenomenon, and general relativity for the observation of the propagation of light rays from a rotating laboratory.

This makes it difficult for engineers working with conventional inertial techniques to understand how these devices work, especially as their mode of operation may involve classical notions of wave optics (interference) with which they are generally unfamiliar.

The aim of this article is precisely to help, by bringing together the basic concepts needed to understand the laser gyrometer and the fiber optic gyrometer, and by giving a brief description of these devices and their performance.