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In this study, generalized Stokes parameters of a phaselocked partially coherent flattopped array beam based on the extended Huygens-Fresnel principle and the unified theory of coherence and polarization have been reported. Analytical formulas for 2 × 2 crossspectral density matrix elements, and consequently Stokes parameters of a phaselocked partially coherent flattopped array beam propagating through the turbulent atmosphere have been formulated. Effects of many physical attributes such as wavelength, turbulence strength, flatness order and other source parameters on the Stokes parameters, and therefore spectral degree of polarization upon propagation have been studied thoroughly. The behaviour of the spectral degree of coherence of a delineated beam for different source conditions has been investigated. It can be shown that four generalized Stokes parameters increase by raising the flatness order at the same propagation distance. Increasing the number of beams leads to a decrease in the Stokes parameters to zero slowly. The results are of utmost importance for optical communications.

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Using the extended Huygens-Fresnel principle in this paper, a semi analytical expression for describing the on-axis scintillation index of a partially coherent flat-topped array laser beam through slant path of non-Kolmogorov atmospheric turbulence is derived; consequently, with the help of the log-normal intensity probability density function, the bit error rate (BER) is evaluated. The main aims of this paper are exploring the effects of source factors (such as wavelength, order of flatness, and beam width) and the non-Kolmogorov turbulent atmosphere parameters (such as Kolmogorov inner scale, general spectral power-law exponent, the turbulence structure constant) on propagation behaviour of scintillation index, and, hence, on BER. Results indicate that, when the average SNR increases, BER is more affected while the power-law exponent increases. Consequently, it can be deduced that the mean bit error rate increases while the power-law exponent decreases. In addition, the scintillation index and BER as communication link parameters represent the fact that increasing the atmospheric refractive-index structure parameter on the ground and decreasing the inner scale of turbulence eddies, which expresses the conditions of strong turbulence, causes an increase in theses link parameters.