Reduction of nonreciprocal errors in a differential interferometric fiber optical gyroscope using optically differential processing

The bias stability of differential interferometric fiber optical gyroscope is analyzed. Thermal error causing long-term bias drift are reduced by putting the 90° splice in the middle of the fiber coil and applying a wide spectrum light source. Also, a kind of novel optical differential processing, which is much more precise than the electronic differential processing, is proposed for reducing the residual nonreciprocal error in the final differential output. An experimental setup based on optical differential processing was built. An ～100 fold reduction in the long-term bias drift is demonstrated experimentally compared with the primary differential interferometric fiber optical gyroscope.