Approximation of orbital angular momentum scintillation

The scintillation index was one crucial parameter to estimating communication system performance. This study investigated the scintillation index of the fundamental mode of the Bessel Gaussian beam and its approximation. The integral expression of the scintillation index was derived, and the influence of the sampling number to the scintillation index was investigated. Moreover, the approximate method of the scintillation and its application condition was also studied. There was a minimum scintillation along the radial direction, and the minimum scintillation along the radical direction was similar with the same product of the propagation distance and the refractive index structure constant. This paper was conductive to the scintillation investigation and provided theoretical basis for the communication link design.