Estimation of gyro bias drift due to distributed polarization cross coupling in the fiber coil

Distributed polarization cross coupling (PCC) along the polarization-maintaining fiber (PMF), obtained from an optical coherence domain polarimetry (OCDP) system, is analyzed. It is found that the measured PCC data at each measurement location is the sum of the OCDP source coherence function centered at a series of discrete PCC points, which do not represent the true PCC information. An algorithm is developed to extract the “true” location and strength of the PCC and the extracted PCC data are no longer source dependent. A model is developed to relate the extracted PCC data in the PMF coil to the fiber optic gyro (FOG) bias drift due to coherent PCC. Experimental results obtained with a FOG with a ~3 km PMF coil and light sources of different bandwidths agree with the theoretically estimated bias drifts.