The channel capacity of the free space communication link based on Bessel-like beams

This study investigates the information channel capacity of free-space communication links based on Bessel-like beams (BLBs) and compares it to that of conventional Gaussian beams (GBs). We examine optical communication links employing amplitude coding for beams with BLB spatial field distribution and orbital angular momentum (OAM)-based coding for single-photon optical communication. Our study explores both unperturbed and perturbed propagation scenarios, considering random phase fluctuations caused by atmospheric turbulence and amplitude attenuation due to absorbing obstacles. Our results show that BLBs provide higher channel capacity than GBs at short distances (within a few kilometers of propagation distance), but GBs outperform BLBs at longer distances. In turbulent environments, BLBs experience more significant capacity degradation than GBs, though they maintain higher capacity in OAM-based single-photon links for distances under 1-2 km.