Measuring Method of Depolarizer Characteristic Parameters in Depolarized Fiber Optic Gyroscope

The output spectrum of Sagnac interferometer assembly of depolarized fiber optic gyroscope (DFOG) was modeled and the results of simulation and experiment show that the output spectrum is the coherently modulated spectrum of incident broadband source. The self-correlation curves of the coherently modulated spectrum were calculated and it was found that the position and amplitude of self-correlation peaks are determined by the length of PMFs and the intersection angle between the polarization axes of two polarization maintaining fibers at joint points. Then, a measuring method of depolarizer characteristic parameters is proposed and investigated theoretically and experimentally and the length of the PMFs and the angular deviation of the depolarizer are measured. The proposed method has high sensitivity and provides an effective method for monitoring and evaluating the parameters of the depolarizer in DFOG.