Patent ID: 7230686

Claim:
Gyrolaser to measure the angular speed or the relative angular position according to a set rotation axis, comprising at least: a ring-shaped optical cavity; a solid-state amplifying medium; a slaving device including at least a first optical assembly made up of a first nonreciprocal optical rotator and an optical element, said optical element being either a reciprocal optical rotator or a birefringent element, with at least one of the effects or the birefringence being adjustable; a measuring instrument; a second optical assembly made up of a first spatial filtering device and of a first polarization separation optical element; a third optical assembly made up of a second spatial filtering device and of a second polarization separation optical element, the second and third optical assemblies being located at either side of the first optical assembly, each symmetrical to the other; a fourth optical assembly made up successively of a first quarter waveplate, a second nonreciprocal optical rotator and a second quarter waveplate whose main axes are perpendicular to those of the first quarter waveplate; such that a first linearly polarized propagation mode and a second propagation mode polarized linearly perpendicular to the first, can propagate in a first direction in the cavity, and a third propagation mode polarized linearly parallel to the first mode and a fourth propagation mode polarized linearly parallel to the second mode can propagate in the opposite direction in the cavity, with the main axes of the first quarter waveplate and the second quarter waveplate tilted 45 degree relative to the linear polarization directions of the four propagation modes, and the optical frequencies of the four modes all being different.