Resonator fiber optic gyro with high backscatter-error suppression using two independent phase-locked lasers

A resonator fiber optic gyro was constructed using separate lasers for counter-rotating waves to overcome interference between optical backscatter and signal light that causes dead-zone behavior and scale factor nonlinearity. This approach enabled a 2 MHz frequency separation between waves in the resonator; eliminating the intended backscatter error. The two lasers were phase-locked to prevent increased gyro noise due to laser frequency noise. Dead-band-free operation near zero-rate, scale factor linearity of 25 ppm and stability of 11 ppm were demonstrated ─ the closest results to navigation-grade performance reported to date. The approach is also free of impractical frequency shifter technology.