Fiber Coupling Efficiency of Partially Coherent Gaussian Beam in Ground-to-HAP Free-Space Optical Communication Systems

Abstract

In this paper, we propose a novel model of fiber coupling efficiency based on the second-order moment interaction of optical field in the oblique atmospheric channel laser communication system, where the turbulence of the partially coherent Gaussian beam propagation can vary in intensity from weak to strong. Based on this model, we analyze the impacts of channel characteristics, reception aperture, and other key system parameters on the fiber coupling efficiency of our considered systems. The numerical results validate the correctness of our model and analysis. Moreover, we show how fiber coupling efficiency can be improved by judiciously selecting the wavelength, coupling lens aperture, focal length, beam size, and the coherence. The results presented in this paper provide pivotal insights into designing practical transmission schemes in optical communication systems.