Patent ID: 8587788
Filing Date: 2013-11-19
Classification: G01C

Abstract:
1. A laser gyro for measuring an angular velocity or a relative angular position along a defined rotation axis, comprising: an optical ring cavity; a solid-state amplifying medium; and a non-reciprocal magneto-optic device; being arranged so that four propagation modes can propagate within the optical ring cavity, the first propagation mode and the third propagation mode being linearly polarized in the same direction, the second propagation mode and the fourth propagation mode being linearly polarized perpendicular to the first propagation mode and to the third propagation mode, the first propagation mode and the second propagation mode propagating in a first direction in the optical ring cavity, the third propagation mode and the fourth propagation mode propagating in an opposite direction of the first direction in the optical ring cavity, and the non-reciprocal magneto-optic device introduces a frequency bias between the first propagation and the third propagation modes propagating in the first direction and the second propagation and the fourth propagation modes propagating in the opposite direction, and wherein said optical ring cavity also includes a stabilizer device for stabilizing an intensity of the four propagation modes at substantially equivalent levels, said stabilizer device comprising at least one optical element made of a non-linear crystal of a frequency-doubling type, wherein the at least one optical element of the stabilizer device comprises two identical optical elements made of a birefringent crystal which are in the form of plates having parallel plane faces, the parallel plane faces being perpendicular to a propagation axis of the various propagation modes, the two identical optical elements being assembled via a common face, and a crystallographic axis of the first optical element being perpendicular to a crystallographic axis of the second optical element, and wherein the at least one optical element being the birefringent crystal is designed so as to generate, from a propagation mode having a first optical frequency (λ