Experimental investigation of a semiconductor ring laser as an optical gyroscope

Fundamental characteristics of a semiconductor ring laser (SRL) as an optical inertial rotation sensor were reported. An SRL used for experiments had a small semiconductor gain block in a fiber external cavity. Beat frequency was measured by the terminal voltage change of an SRL as a function of the rotation rate, changing the loop radius of an SRL and the turn number of the fiber loop for investigating the detection characteristics. Detection sensitivity was proportional to the loop radius, and was independent of the turn number of the fiber loop. These experimental results verified that SRL´s were operated as active ring laser gyroscopes based on the Sagnac effect. Furthermore, we verified that lock-in phenomenon was one of the most dominant noise sources