Model-Based Wavefront Correction for Adaptive Multi-Aperture Fiber Coupling Array

The Adaptive Fiber Coupler (AFC) array is an innovative device designed to achieve the stable and efficient coupling of free-space light into optical fibers. To mitigate the effects of atmospheric turbulence, the Stochastic Parallel Gradient Descent (SPGD) algorithm has been predominantly adopted as the control method for AFC systems. However, due to the dynamic nature of atmospheric turbulence, the relatively slow convergence speed of the SPGD algorithm poses significant challenges for practical applications. This paper presents a model-based AFC control system that effectively mitigates wavefront aberrations caused by atmospheric turbulence. The performance of this system was evaluated in comparison with the SPGD algorithm under different turbulence levels and different sub-aperture numbers. Results show that the model-based AFC system converges faster than the SPGD-based AFC system under identical conditions. Additionally, the number of iterations required by the model-based AFC system remains relatively stable, whereas the SPGD-based AFC system demonstrates substantial variability depending on the number of sub-apertures and turbulence levels. As the turbulence level increases, the SPGD-based AFC system requires a greater number of iterations to achieve convergence. The proposed model-based method offers a robust and efficient solution for adaptive multi-aperture fiber coupling systems, which provides theoretical and technical support for the practical application of AFC array.