Abstract: Dither compensation in a ring laser gyroscope is effectuated by one or more retroreflective prisms or by one or more pairs of cofunctioning transparent wedges mounted to the gyroscope casing in a dither compensation plane parallel to the plane of the laser light path in the gyroscope cavity. Prisms or beam splitters reflect at least one of two counter-rotating laser beams to the dither compensation plane from the plane of the cavity. An optical sensor comprising a photodiode for detecting and analyzing the interfering laser beams can be placed in the dither compensation plane or in the plane of the gyroscope cavity.

Abstract: A feedback control system for maintaining the intensity and spectral distribution of light at a predetermined level at a wavelength characteristic of the excited source. Control of that intensity, which exhibits a systematic but not necessarily a monotonic relation with excitation, is achieved by measuring and controlling the intensity of flux at another characteristic wavelength which is both systematic and monotonic.