Abstract: A semiconductor ring laser apparatus is provided which comprises a semiconductor laser element having electrical terminals and optical terminals. An electrical power supply means is coupled to the electrical terminals for applying a voltage thereto and optical means are optically coupled to the optical terminals of the semiconductor laser element. The optical means form resonant ring optical paths in clockwise and counterclockwise directions for the light which is emitted by the semiconductor. Detector means are provided which are coupled to said electrical terminals for detecting voltage variations thereon caused by the rotation of the apparatus.