High precision fiber optic gyroscope based on Er-doped superfluorescent fiber source

For high precision fiber optic gyroscope application, high performance Er-doped superfluorescent fiber source was demonstrated and a practical prototype with 2.58 × 10°C mean wavelength stability and less than 1% output power instability within -40°C ∼ +60°C was made with a cut-off type thin film filter which reflect long wavelength light within 1550 nm band and the optimal parameters obtained by simulation. The source relative intensity noise was measured and analyzed. A close loop all digital fiber optic gyroscope prototype was made using this source. With a noise subtracting technology, the noise in fiber optic gyroscope was reduced and the random walk coefficient decreased about 20%. The whole performance of this gyroscope prototype was tested and the bias drift of the fiber optic gyroscope prototype is 0.0045(°)/h and the random walk coefficient is 0.0035(°)/h^1/2 according to the result of Allan variance analysis and its scale factor error is less than 11 × 10. This satisfies the demand of land inertial system.