A Novel Beam Tracking Method for Silicon-Based Optical Phased Array Under Inter-Satellite Vibrations

To meet the miniaturization and lightweight requirements of inter-satellite laser communication, this study investigates the servo control system of a silicon-based optical phased array (OPA). Based on the far-field radiation model for beam steering of the silicon-based OPA, combined with thermo-optic phase modulation technology and time domain response, the transfer function of the silicon-based OPA is established. To address noise and disturbances encountered during actual tracking, a silicon-based OPA beam tracking method for satellite platform vibration is proposed. The control algorithm employs a Kalman filter-based Model Predictive Control (KF-MPC) strategy. The advantages of the designed control algorithm were verified through simulations and experiments. Step response simulation results show that compared with the traditional PID control algorithm, the proposed algorithm reduces overshoot by 15.1% and shortens the response time by 76.4%. Sinusoidal tracking simulation results indicate a 27.15% improvement in tracking accuracy over the traditional PID algorithm. Experimental results demonstrate that the tracking accuracy of the servo control system with the proposed algorithm is 155.45 μrad, while that using the PID algorithm is 210.97 μrad, representing a 26.31% improvement in tracking accuracy. This research provides a valuable reference for the application of silicon-based OPA in inter-satellite laser communication.