Research on the self-biasing frequency mechanism of vector-based dual-longitudinal mode laser gyroscopes

Abstract The explanation of the laser gyro’s self-biasing frequency phenomenon based on the Lamb semi-classical theory is too complicated, and the physical nature of the double longitudinal self-biasing frequency phenomenon cannot be obtained intuitively. To clarify the mechanism of the double longitudinal mode self-biasing phenomenon, this paper deduces the beat frequency equation of the double longitudinal mode laser gyro from the vector form of the light wave, based on the geometrical relationship of the vector phase angle. The results show that the necessary condition for the occurrence of the self-biased frequency phenomenon is the existence of the optical intensity difference between the two beams of the strong mode clockwise and anticlockwise, and to make the self-biasing frequency phenomenon stable, the phase difference between the strong and weak modes has to be locked near π , and the self-biasing frequency phenomenon is significant in the range of intensity ratios between the strong and weak modes of (1, 1.1). Finally, the experimental phenomenon of double longitudinal mode self-biasing frequency is reproduced.