Propagation of the Bessel-Gaussian Beams Generated by Coherent Beam Combining in Oceanic Turbulence

Coherent beam combining (CBC) is recently used to generate high power vortex beams which are strongly required in specific applications. In this paper, based on the extended Huygens-Fresnel principle, the exact theoretical forms for the intensity distribution of CBC Bessel-Gaussian beams (BGBs) in turbulent ocean are derived. To show the superiority of CBC BGBs in turbulent channels, the comparison in the intensity evolution of CBC BGBs with ideal BGBs is performed. It is found that the beam spreading of CBC BGBs is smaller than that of ideal BGBs under the same oceanic turbulence conditions. Moreover, the effect of the beam parameters and channel parameters on the quality of CBC BGBs is also analyzed. The results show that the oceanic turbulence with a higher rate of dissipation of kinetic energy per unit mass of fluid, lower dissipation rate of the mean-squared temperature, or smaller ratio of temperature and salinity contributions to the refractive index spectrum has smaller impact on CBC BGBs. Moreover, the increasing number of the beamlets, the increasing waist width of each beamlet, and the decreasing radius of the beam distribution cause the optical energy to be more concentrated, and thus leading to a longer non-diffraction propagation distance.