A method to improve the modulation depth servo accuracy of an integrated fiber-optic gyroscope using the Bouc-Wen model

•Propose a method to extract the high frequency hysteresis nonlinear of PEM.•A method to improve the precision of gyro depth closed-loop control by feedforward compensation is proposed.•The output drift of integrated fiber optic gyroscope at variable temperature is effectively suppressed.•The hysteretic nonlinear response of the piezoelectric phase modulator at high temperature is reduced, which provides a basis for the temperature compensation scheme.