Multipoint reset modulation for reduced crosstalk in a miniaturized fiber optic gyroscope

With the maturity of slim diameter polarization-maintaining fiber and correlational optical devices, miniaturized interferometric fiber optic gyroscope (MIFOG) developed rapidly, MIFOG has strengthened its lead in tactical and navigation grade, while squeezed the market of ring laser gyroscope (RLG) and MEMS gyroscope. It has obvious advantages in the fields of navigation, attitude control and even civil autonomous driving in the future. Electrical crosstalk is regarded as the most significant factor influencing dead zone, bias error and noise in MIFOG. Studies have shown that circuit filter, isolation structure and multistate modulation can greatly reduce the crosstalk. However, there are many problems in the design and production of MIFOG: the circuit board is too small to use effective filtering measures; the existence of the spatial reflection paths makes the crosstalk control more difficult; the structure is limited by space and cannot be effectively isolated; the limitation of the fiber ring length makes it impossible to use complex multistate modulation. In this paper, an electrical crosstalk error suppression method based on multipoint reset modulation (MRM) is proposed. The mathematical model of the influence of electrical crosstalk on fiber optic gyroscope is established. The electrical crosstalk errors under single point reset (SRM) and MRM are analyzed through simulation and test. The results show that the electrical crosstalk errors under MRM reset can be reduced by more than 20% compared with SRM reset at a modulation depth of 2π/3. Furthermore, the crosstalk of MRM diminishes as the modulation depth increases, and it accords with the theory of signal-to-noise ratio (SNR) that needs modulation depth close to π to suppress the excess relative intensity noise (RIN) of the light source. The research in this paper is of great significance to the performance improvement of the MIFOG.