Multi-Oscillator Solid-State Laser Gyro Passively Stabilized by a Frequency-Doubling Crystal Device

A laser gyro for measuring the angular velocity or the relative angular position along a defined rotation axis, comprising:

• on 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 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 mode and to the third mode, the first propagation mode and the second propagation mode propagating in a first direction in the cavity, the third propagation mode and the fourth propagation mode propagating in the opposite direction in the cavity, and the magneto-optic device introducing a frequency bias between the modes propagating in the first direction and the modes propagating in the opposite direction, and
• wherein said cavity also includes a stabilizer device for stabilizing the intensity of the four propagation modes at substantially equivalent levels, said device comprising at least one optical element made of a non-linear crystal of the frequency-doubling type.