Free-space optical communication is an effective alternative solution to address the “last mile” bottleneck in fiber-optic communication systems. However, its practical performance is significantly affected by phase perturbations and intensity scintillation induced by atmospheric turbulence effects. This paper proposes a multi-aperture adaptive fiber-coupled communication architecture, systematically investigating the optical transmission characteristics in turbulent channels through a combined approach of theoretical modeling and experimental validation. Utilizing the Gamma-Gamma turbulence channel model, quantitative analyses are conducted to elucidate the relationships between the scintillation index, the number of transmitting apertures, and the bit error rate. By establishing an outdoor 2.1 km experimental platform, we demonstrate that multi-aperture diversity transmission combined with closed-loop control reduces the scintillation index by 60% while achieving 10 Gbit/s error-free communication under weak turbulence conditions. Experimental results indicate that the proposed architecture enhances coupling power while maintaining high communication quality. Its modular design ensures high compatibility with mature fiber-optic communication components, providing a solution for constructing low-complexity, high-reliability hybrid optical communication systems in urban environments.