Method for suppressing the bias drift of interferometric all-fiber optic gyroscopes

We propose a simple and, to our knowledge, novel method for suppressing the bias drift of interferometric all-fiber optic gyroscopes (I-FOGs) and for self-calibrating the bias of I-FOGs to zero. Using a square wave to reverse the polarity of the sinusoidal voltage on a piezoelectric (PZT) modulator periodically, and calculating the output signal of a demodulator circuit in-phase with the square wave by a digital signal processor (DSP), we successfully reduce the bias drift of I-FOGs. Experimental results show that, at room temperature, the proposed method dramatically reduces the bias instability of an I-FOG from 0.201 deg/h to 0.102 deg/h. With this method, the I-FOGs no longer need zero calibration.