Maksutov–Cassegrains are widely used in free-space optical communication. The coupling efficiency and variance of a Maksutov–Cassegrain fiber (single-mode) system distorted by atmospheric turbulence are numerically evaluated using second-order and fourth-order moments under a Von Karman spectrum. Considering the limited cost and size of the equipment, the Maksutov–Cassegrain aperture should satisfy $D_A/{\rho }_S\approx 7$ (${\rho }_S$ approximates the characteristic atmospheric coherence length), and the obscuration ratio should be no more than 0.2.

Partially coherent optical vortices have been applicated widely to reduce the influence of atmospheric turbulence, especially for free-space optical (FSO) communication. Furthermore, the beam array is an effective way to increase the power of the light source, and can increase the propagation distance of the FSO communication system. Herein, we innovatively report evolution properties of the radial phased-locked partially coherent vortex (RPLPCV) beam array in non-Kolmogorov turbulence. The analytical expressions for the cross-spectral density and the average intensity of an RPLPCV beam array propagated through non-Kolmogorov turbulence are obtained. The numerical results reveal that the intensity distribution of the RPLPCV array propagated in the non-Kolmogorov turbulence is gradually converted to a standard Gaussian distribution. In addition, the larger the radial radius, radial number and waist radius are, the smaller the coherence length is. Moreover, the longer the wavelength is, the shorter the propagation distance required for the intensity distribution of the RPLPCV beam array to be converted into a Gaussian distribution in the non-Kolmogorov turbulence. The research in this paper provides a theoretical reference for the selection of light sources and the suppression of turbulence effects in wireless optical communication.

When a signal beam propagates through the atmosphere, it is affected by turbulence. The Airy beam, with its characteristics of diffraction-free propagation, self-healing, and self-focusing, can effectively mitigate the adverse effects of atmospheric turbulence. In this paper, the coupling efficiency is constructed based on the theory of cross-spectral density, using a structure consisting of partially coherent Airy beams, a single lens, and a four-mode optical fiber. In addition, we also investigated the effects of atmospheric turbulence, lens parameters, and beam parameters on the coupling efficiency. The results indicate that under moderate turbulence conditions (scintillation index A_R/A_C = 5), the coupling efficiency of the partially coherent Airy beams is 25.7% higher than that of the Gaussian-Schell model beams.