Ring Laser Gyro Resonator Design

Ring laser gyroscopes RLGS have been used for navigation on the Atlas II launch vehicle and are scheduled for the Titan IV and Delta launch vehicles. The typical launch vehicle random-vibration environment could cause errors in measured RLG rotation rates due to vibration tilt of the resonator mirrors. Vibration-induced mirror tilt can create a variation in laser power due to laser beam occlusion by the intracavity mode control apertures. In the present work, we have analyzed the RLG resonator design theoretically and calculated pertinent parameters such as the beam diameter at the aperture, cavity mirror alignment sensitivities, and power loss due to aperture occlusion. The mirror vibration levels required to significantly affect the laser power were then calculated for typical RLG resonator geometries. It is concluded that vibration-induced bending of a typical RLG resonator structure should not cause a significant loss in laser power.