Angular velocity measurement system based on optical frequency comb

The optical frequency comb (OFC) is an emerging laser light source, which has laid the foundation for high resolution, high sensitivity, wide bandwidth and fast measurement. Angular velocity measurement as an important direction in the field of measurement has been paid attention. Nowadays, fibre optic gyroscope (FOG) is usually used to measure angular velocity. The Sagnac effect is the theoretical basis of FOG. Therefore, it is especially important to verify whether the FOG has Sagnac effect. Through theoretical derivation, when the FOG is used as a light source in combination with Sagnac interferometer and the Sagnac interferometer rotates at different angular velocities, the trigonometric function reflects the mutual transformation of the intensity of the light emitted by the interferometer and angular velocities, and the corresponds nonlinear relationship. This proves that FOG has Sagnac effect. When repetition frequency of FOG is locked,this system can be used to measure angular velocity. In the experiment, we use 1km single-mode fiber as the rotating part of Sagnac interferometer, and measure the light intensity value at 20 different angular velocities. Measuring 10 times at each angular velocity for the mean value, which are used to fit the trigonometric function curve. The results show that the correlation coefficient of the fitting curve is greater than 0.99, and standard deviations of the measurement points are less than 0.06V. The corresponding angle error values at different angular velocities are converted into the distance errors, which are less than 0.032um.