Adjustment-free method to eliminate the noise induced by the backscattering in an optical passive ring-resonator gyro

An adjustment-free method to eliminate the noise induced by the interference between the signal wave and the backscattering in an optical passive ring-resonator gyro is proposed and demonstrated. In this method, the lightwave incident into the ring resonator is modulated by binary shift keying to eliminate its carrier component. This can easily be performed by using an acoustooptic modulator and a double balanced mixer. In the experiment, the noise is successfully reduced without any adjustment of the modulation parameters.<>