Two-color Brillouin ring laser gyro with gyro-compassing capability

We investigated the gyro-compassing capability of a Brillouin ring laser gyro set up in a two-color operation. Two counterpropagating pump lasers initiated two Brillouin ring lasers on different resonances of a fiber-optic ring resonator cavity, which excluded the mutual intracavity interaction between both counterpropagating Brillouin lasers. Additionally minimizing the external feedback channels of the individual Brillouin lasers allowed for high-resolution measurements, e.g., the horizontal component of the Earth's rotation rate (10.0 degrees /h at Uberlingen, Germany, which corresponded to a beat frequency of 6.85 Hz).