Analysis Of Optical Waves Propagation Characteristics Inanisotropic Maritime Atmospheric Turbulence

Until now,the propagation characteristics of optical waves in atmospheric turbulence have been extensively studied in terrestrial environments.However,the marine atmospheric turbulence must not only consider the fluctuation of temperature but also take the fluctuation of humidity into consideration,so that the propagation characteristics of optical waves in the marine atmospheric turbulence are different from in the terrestrial atmosphere.Based on the atmospheric turbulence power spectrum proposed by Yong et al.for the general marine environment,the turbulence effects of optical waves propagation in the marine atmospheric have been studied.However,these studies are based on the Kolmogorov turbulence theory and assume that the marine atmospheric turbulence is homogeneous and isotropic.In order to better develop the optical communication at marine atmospheric,it is of great significance to study the propagation characteristics of the optical waves in the anisotropic non-Kolmogorov marine atmospheric turbulence.Based on Rytov approximation theory for weak turbulence and the anisotropic non-Kolmogorov marine power spectrum model,the turbulent effects of Gaussian beams,long-exposure turbulence modulation transfer functions(MTF)for plane and spherical waves,and the probability density and the relative power of the orbital angular momentum(OAM)for Gaussian vortex beam and Hankel-Bessel-Shell(HBS)vortex beam are theoretically deduced.The corresponding analytic expressions are obtained,and detailed numerical calculation and analysis are performed.The results show that:(1)the anisotropy of the marine turbulence has a weakening effect on the turbulence effects of the Gaussian beam.The more severe the anisotropy is,the smaller the turbulence effect.(2)When the marine atmospheric turbulence exist anisotropy,the long-exposure turbulence MTF of optical waves is less affected by turbulence than the effect of isotropic marine atmospheric turbulence.When the wavelength of optical wave is longer,the value of long-exposure turbulence MTF of optical wave propagation in anisotropic non-Kolmogorov marine atmospheric is smaller.And under the same conditions,the image quality of the spherical wave is better than that of plane wave.It plays an important role in the selection of the optical source for the imaging system.(3)For the optical communication system based on orbital angular momentum,the presence of anisotropy in the marine atmospheric turbulence has a dampening effect on the noise,and the received power of the orbital angular momentum model will increase accordingly.The greater the anisotropy coefficient is,the greater the received power.The optical communication system selecting a vortex beam with smaller OAM quantum number and longer wavelength as optical source can achieve better communication performance.When the system selects a Gaussian vortex beam as optical source,there is a wavelength-dependent optimal waist,and the waist makes the best communication performance.When the HBS vortex beam is used as the optical source,the mode probability density and the received power of the orbital angular momentum module of the fully coherent HBS beam are better than those of the partially coherent HBS beam.