The field of the invention is that of solid-state laser gyros. One of the major problems inherent in this technology is that the optical cavity of this type of laser gyro is by nature highly unstable. To reduce this instability, the invention proposes to introduce, into the cavity, controlled optical losses that depend on the direction of propagation by using acoustooptic devices. Several devices are described, employing different configurations of acoustooptic devices. These devices apply in particular to laser gyros having monolithic cavities, and in particular to neodymium-doped YAG laser gyros.