The noise suppression in resonant micro optic gyroscopes based on dual light sources method

Abstract In Resonant Micro-Optical Gyroscopes (R-MOG), optical backscatter noise is generally considered to be one of the largest noises which also greatly limits the improvement of accuracy. A suppression method based on dual light sources is designed in this paper, in which two tunable semiconductor lasers are used to provide light for clockwise (CW) and counterclockwise (CCW), respectively. Two independent lasers have been frequency divided and phase locked by Optical Phase-Locked Loop (OPLL). In this way, high-frequency noise caused by interference between the backscatter light and the signal light can be filtered out, completely. The frequency noise for dual-lasers has also been effectively suppressed by adjusting the OPLL bandwidth. Then, intensity modulators with second harmonic feedback have been used to achieve the stabilization of the optical power in the cavity. The results show that, the influence of the interfering light intensity is reduced by about an order of magnitude compared with the single-phase modulation technology in single laser system and the bias stability has stood at 0.00448 ∘ /s.