Research on light source average wavelength and crystal oscillator frequency for reducing temperature error of the FOG scale factor

Based on the working principle of the digital closed-loop fiber optic gyroscope (FOG), a model for the influence of crystal oscillator frequency on scale factor (SF) temperature error is theoretically derived. Besides, the correlation between the two main light sources average wavelength and the SF temperature error is discussed. The experimental results show that both the crystal oscillator frequency and the light source average wavelength have a greater impact on the FOG SF temperature error. There is a cubic function relationship between crystal oscillator frequency and temperature, the temperature error of the SF is inversely proportional to the crystal oscillator frequency. Using a higher frequency temperature-compensated crystal oscillator, the frequency stability can be improved by two orders of magnitude, from 67.14 ppm to 0.22 ppm, the SF temperature error is also greatly reduced. The SF error is proportional to the relative change in wavelength, and the change caused by the temperature is of the same order of magnitude. Compared with the super luminescent diode (SLD) light source, the Erbium-doped fiber light source has higher average wavelength stability, the SF error caused by it is also smaller. The error can be reduced by 15 ppm and controlled at about 10 ppm after temperature compensation.