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.

This paper experimentally discovers the self-biasing effect induced by the Lamb dip in a dual-longitudinal-mode laser gyroscope and provides a theoretical explanation for this effect using the semi-classical theory of laser oscillation. The operational characteristics of single- and dual-longitudinal-mode laser gyroscopes are elucidated based on the relationship between power tuning curves and the control error of small-dither AC frequency stabilization. Furthermore, the reason why the average light intensity of a dual-longitudinal-mode self-biasing laser gyroscope is lower than that of a single-mode counterpart is explained using the principle of beat frequency. Additionally, by analyzing the relationship between the power tuning curve and the output pulse count of the dual-longitudinal-mode laser gyroscope, it is demonstrated that a self-biasing effect occurs at the Lamb dip, where the cavity tuning frequency is approximately ±440 MHz. On this basis, the beat frequency equation of the dual-longitudinal-mode laser gyroscope is studied using the self-consistent equation theory, and a functional expression for the self-biasing magnitude is derived. The research indicates that the gain saturation coefficient and the frequency mutual repulsion coefficients of the strong and weak modes provide the optical bias for the dual-longitudinal-mode self-biasing laser gyroscope. The findings of this study offer an important reference for achieving long-term stable operation of the dual-longitudinal-mode self-biasing laser gyroscope.

A novel double-memristor-based chaotic system (DMCS) is proposed in this paper to address limitations in traditional chaos generation methods. Two identical memristors are introduced into the first and third dimensions of a chaotic system, creating a unique platform for investigating extreme multi-stability induced by the memory characteristics of the memristors. Diverse coexisting attractors are observed, with variations in initial conditions resulting in shifts in both the position and size of the attractors. Additionally, cross-dimensional control of multistability is achieved, where the stability in one dimension is influenced by initial values in other dimensions, leading to symmetric attractor arrangements under specific conditions. An inverse regulation of the attractor oscillation range is enabled by adjusting the memristor coupling strength, providing a novel chaotic signal tuning mechanism. The system’s chaotic dynamics are validated through a circuit implementation in Multisim, where fundamental behaviors predicted by theoretical analysis are confirmed. A pseudo-random number generator (PRNG) based on the DMCS is developed, demonstrating exceptional randomness as verified by rigorous testing.

In view of the phenomenon that the scale factors of the laser gyro with total reflection prism changes periodically with temperature, the influence of temperature changes on the ring laser area under the condition of frequency stabilization was studied by matrix optical method. The relationship between the scale factors of the laser gyro with total reflection prism and the frequency stabilization voltage was obtained, and it was pointed out that the beam offset was the cause of the periodic change of scale factors with temperature. According to the relationship between the scale factors and the frequency stabilization voltage, the scale factor compensation model of the laser gyro with total reflection prism was established, and the nonlinearity of the scale factors before and after compensation was compared through experiments. The results show that the nonlinearity of the scale factors is increased by more than one order of magnitude by using the proposed model to compensate the scale factors of the laser gyro with total reflection prism. The research has certain reference value for improving the performance of laser gyro with total reflection prism.

Gallium arsenide (GaAs) is widely used in high-frequency and optoelectronic devices, but its brittleness challenges the simultaneous achievement of high material removal efficiency and surface quality. This study employs molecular dynamics (MD) simulations to examine the effects of vibration-assisted grinding (VAG) on GaAs nanomachining, focusing on three vibration periods: 20 ps, 70 ps, and 120 ps. The results indicate that VAG enhances the material removal rate (MRR) and reduces subsurface damage compared to conventional grinding. A vibration period of 70 ps offers the optimal balance, improving MRR by approximately 3% and reducing surface roughness by approximately 14%. While a shorter period (20 ps) further increases MRR, it also elevates surface roughness and residual stress. Conversely, a longer period (120 ps) improves surface integrity at the expense of material removal efficiency. Moreover, VAG reduces friction and promotes more uniform atomic flow, with the 70 ps condition showing the most significant improvements. These findings provide theoretical guidance for optimizing GaAs wafer processing in micro- and nanoscale device fabrication.

In this work, an adaptive robust control method based on Radial Basis Function Neural Network (RBFNN) is proposed. Inspired by the local response characteristics of biological neurons, this method can reduce the influence of nonlinear errors and unknown perturbations in the extreme working conditions of the aircraft, such as high dynamics and strong vibration, so as to achieve high tracking accuracy. In this method, the dynamic model of the nonlinear error of the fiber optic gyroscope is proposed, and then the unknown external interference observer is designed for the system to realize the estimation of the unknown disturbances. The controller design method combines the design of the adaptive law outside the finite approximation domain of the achievable condition design of the sliding mode surface, and adjusts the controller parameters online according to the conditions satisfied by the real-time error state, breaking through the limitation of the finite approximation domain of the traditional neural network. In the finite approximation domain, an online adaptive controller is constructed by using the universal approximation ability of RBFNN, so as to enhance the robustness to nonlinear errors and external disturbances. By designing the output constraint mechanism, the dynamic stability of the system is further guaranteed under the constraints, and finally its effectiveness is verified by simulation analysis, which provides a new solution for high-precision inertial navigation.