Mitigating the effect of atmospheric turbulence on orbital angular momentum-based quantum key distribution using real-time adaptive optics with phase unwrapping

TL;DR

This paper investigates how real-time adaptive optics can mitigate atmospheric turbulence effects on orbital angular momentum-based quantum key distribution, improving security and capacity in turbulent conditions.

Contribution

It introduces a novel analysis using infinitely long phase screens and evaluates AO performance under phase cuts, demonstrating real-time correction benefits.

Findings

AO improves OAM-QKD performance under moderate turbulence

Real-time AO remains effective at high wind velocities

Phase cuts impact correction quality but can be mitigated

Abstract

Quantum key distribution (QKD) employed orbital angular momentum (OAM) for high-dimensional encoding enhances the system security and information capacity between two communication parties. However, such advantages significantly degrade because of the fragility of OAM states in atmospheric turbulence. Unlike previous researches, we first investigate the performance degradation of OAM-based QKD by infinitely long phase screen (ILPS), which offers a feasible way to study how adaptive optics (AO) dynamically corrects the turbulence-induced aberrations in real time. Secondly, considering the failure of AO while encountering phase cuts, we evaluate the quality enhancement of OAM-based QKD under moderate turbulence strengths by AO after implementing the wrapped cuts elimination. Finally, we simulate that, with more realistic considerations, real-time AO can still mitigate the impact of atmospheric turbulence on OAM-based QKD even in the large wind velocity regime.