Comparison of Gaussian and vortex beams in free-space QKD with phase encoding in turbulent atmosphere

At present, free-space QKD systems are being actively researched and developed. The main limitation of these systems remains the strong influence of atmospheric turbulence and weather conditions on the propagating Gaussian beam. In turn, a number of works have shown that vortex beams are more stable in a turbulent atmosphere. Thus, in this work, the use of vortex beams in the free-space QKD system with phase encoding under the condition of a turbulent atmosphere and their comparison with Gaussian beams are studied. The possibility of phase modulation preservation with additional modulation and demodulation of the vortex beam is also investigated.