This invention is an entanglement-based continuous variable-quantum key distribution (CV-QKD) scheme that performs information reconciliation over the entanglement assisted communication link. The same entanglement generation source is used in both raw key transmission and information reconciliation. Experimental demonstrations over the free‐space optical testbed established at the University of Arizona campus indicate that the proposed CV‐QKD scheme with information reconciliation over the entanglement assisted link significantly outperforms corresponding CV-QKD scheme with information reconciliation over the authenticated public channel. It also outperforms the CV‐QKD scheme in which classical free‐space optical communication link is used to perform the information reconciliation, and was found to operate in strong turbulence regime. Background: Strong turbulence regime poses different technical challenges with quantum communications technologies in areas such as terrestrial free-space optical links, uplink to high-altitude platform systems (HAPS), uplink/downlink to/from satellites, near-Earth applications, and underwater communications, to mention a few. Entanglement, or the strong correlation between particles, as used in quantum communication can help beat classical channel capacities, achieve better than classical sensors sensitivity, and provide quantum-mechanics based security. Different photon degrees of freedom can be utilized in QKD including polarization, time, frequency, phase, and orbital angular momentum. Among different QKD protocols, discrete variable (DV)‐QKD and continuous variable (CV)‐QKD are very popular ones. In DV‐QKD schemes, a single photon detector (SPD) is applied, while CV‐QKD relies on uncertainty principle. With CV‐QKD one can achieve higher secret key rates (SKRs) compared to corresponding DV‐QKD schemes thanks to its compatibility with the state‐of‐the‐art telecom optical communications. Applications:
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