Patent ID: 7710575

Claim:
A laser gyro comprising at least one ring-shaped optical cavity and a solid-state amplifying medium which are arranged so that first and second optical waves can propagate in opposite directions within the cavity, wherein the cavity comprises: first optical means for imposing a first linear polarization state common to the two counterpropagating optical waves outside the zone containing the amplifying medium; and second optical means defining the zone containing the amplifying medium and for imposing, within this zone, a second linear polarization state on the first optical wave and a third linear polarization state on the second optical wave, these two polarization states being perpendicular; wherein the second means are two Faraday rotators, the first placed at the entrance of the amplifying medium and the second at the exit of the amplifying medium, the first providing a 45° rotation of a polarization state in a first direction and the second providing a 45° rotation of a polarization state in the opposite direction.