Crosstalk probability of the bandwidth-limited orbital angular momentum mode of Bessel Gaussian beams in marine-atmosphere turbulence

The diffraction of the beam edges affects the transmission of the orbital angular momentum (OAM) mode carried by vortex beam. Based on the bandwidth-limited OAM orthogonal vortex basis set, we study the crosstalk probability of the OAM mode carried by the Bessel Gaussian beam in marine-atmosphere turbulence. We find that the crosstalk probability of the bandwidth-limited OAM mode is larger than that of the spiral plane mode. The crosstalk probability of the bandwidth-limited OAM mode decreases with the increment of the inner scale of turbulence, but this crosstalk probability increases with the increment of the outer scale of turbulence. A Bessel Gaussian beam with optimum initial radius of beam, and long beam wavelength in the transmission window is preferable for application. The energy of the OAM mode primarily spreads to adjacent state. Our research confirms that the beamwidth factor of OAM mode should be added to the study of free-space optical communication to make the calculation results closer to the realistic situations.