Measurement-device-independent quantum key distribution (MDI-QKD) protocol has high practical value. Satellite-based links are useful to build long-distance quantum communication network. The model of satellite-based links for MDI-QKD was proposed but it lacks practicality. This work further analyzes the performance of it. First, MDI-QKD and satellite-based links model are introduced. Then considering the operation of the satellite the performance of their combination is studied under different weather conditions. The results may provide important references for combination of optical-fiber-based links on the ground and satellite-based links in space, which is helpful for large-scale quantum communication network.
Measurement-device-independent quantum key distribution (MDI-QKD) protocol has high practical value. Satellite-based links are useful to build long-distance quantum communication network. The model of satellite-based links for MDI-QKD was proposed but it lacks practicality. This work further analyzes the performance of it. First, MDI-QKD and satellite-based links model are introduced. Then considering the operation of the satellite the performance of their combination is studied under different weather conditions. The results may provide important references for combination of optical-fiber-based links on the ground and satellite-based links in space, which is helpful for large-scale quantum communication network.
Abstract Measurement-device-independent Quantum conference key agreement (MDI-QCKA) shares secure keys among multiple users by distributing postselected Greenberger-Horne-Zeilinger (GHZ) entanglement, improving practicality and security. Currently, the proposed QCKA protocols can achieve a communication distance of hundreds of kilometers over fiber link. However, such performance is only applicable to quantum communication within an inter-city range. To enable multi-user communication to cover a broader area, quantum satellites offer a solution. Here, one of the communication parties of MDI-QCKA is set as a satellite, and its performance is analyzed in combination with the characteristics of satellite-based link. Simulation results demonstrate the impact of the asymmetry of satellite-based and fiber link on system performance. In addition, considering the fluctuation of satellite-based link, the limitations on system performance caused by atmospheric turbulence, scattering particles, and pointing error are also simulated. These results provide a detailed analysis of the performance of satellite-based MDI-QCKA from the perspectives of satellite operation and the atmospheric environment, contributing to the expansion of MDI-QCKA to future global quantum communication networks.
Abstract The establishment of a world-wide quantum communication network relies on the synergistic integration of satellite-based links and fiber-based networks. The first are helpful for long-distance communication, as the photon losses introduced by the optical fibers are too detrimental for lengths greater than about 200 km. This work aims at giving, on the one hand, a comprehensive and fundamental model for the losses suffered by the quantum signals during the propagation along an atmospheric free-space link. On the other hand, a performance analysis of different quantum key distribution (QKD) implementations is performed, including finite-key effects, focusing on different interesting practical scenarios. The specific approach that we chose allows to precisely model the contribution due to different weather conditions, paving the way towards more accurate feasibility studies of satellite-based QKD missions.
In this work, an estimation of the key rate of measurement-device-independent quantum key distribution (MDI-QKD) protocol in free space was performed. The examined free space links included satellite-earth downlink, uplink and intersatellite link. Various attenuation effects were considered such as diffraction, atmosphere, turbulence and the efficiency of the detection system. Two cases were tested: asymptotic case with infinite number of decoy states and one-decoy state case. The estimated key rate showed the possibility of applying MDI-QKD in earth-satellite and intersatellite links, offering longer single link distance to be covered.
Abstract The measurement-device-independent (MDI) quantum key distribution (QKD) is considered to be an alternative to overcome the currently trusted satellite paradigm. However, the feasibility of the space-based MDI-QKD remains unclear in terms of the factors: the high-loss uplink between a ground station and a satellite, the limited duration when two ground stations are simultaneously visible, as well as the rigorous requirements for the two-photon interference when performing the Bell-state measurement. In this paper, we present a feasibility assessment of space-based MDI-QKD based on the Micius satellite. Integrated with the orbital dynamics model and atmosphere channel model, a framework is presented to explore the whole parameters space including orbit height, elevation angle, apertures of transceiver and atmospheric turbulence intensity to give the considerations for improving key rates and subsequently provide a relevant parameter tradeoff for the implementation of space-based MDI-QKD. We further investigate the heart of MDI-QKD, the two-photon interference considerations such as the frequency calibration and time synchronization technology against Doppler shift, and the way of performing the intensity optimization method in the dynamic and asymmetric channels. Our work can be used as a pathfinder to support decisions involving as the selection of the future quantum communication satellite missions.
Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted relays. Since the MDI-QKD protocol was proposed, fiber-based implementations aimed at longer distance, higher key rates, and network verification have been rapidly developed. However, owing to the effect of atmospheric turbulence, MDI-QKD over a free-space channel remains experimentally challenging. Herein, by developing a robust adaptive optics system, high-precision time synchronization and frequency locking between independent photon sources located far apart, we realized the first free-space MDI-QKD over a 19.2-km urban atmospheric channel, which well exceeds the effective atmospheric thickness. Our experiment takes the first step toward satellite-based MDI-QKD. Moreover, the technology developed herein opens the way to quantum experiments in free space involving long-distance interference of independent single photons.
Abstract This study investigates the feasibility of the phase‐matching measurement‐device‐independent quantum key distribution (PM‐MDI QKD) protocol proposed by Lin and Lütkenhaus for satellite‐based quantum communication. The protocol's key rate, known to exceed the repeaterless PLOB bound, is evaluated in the asymptotic limit under noisy conditions typical of satellite communications, including loss‐only scenarios. The setup involves two ground‐based parties connected via fiber (loss‐only or noisy) and a space‐based third party linked to one of these two ground‐based parties through free‐space communication. Simulations using the elliptic‐beam approximation model the average key rate (AKR) and its probability distribution (PDR) across varying zenith angles and fiber distances. Down‐link free‐space communication is assessed under day and night conditions, with intensity optimization for each graphical point. Dynamic configurations of satellite and ground stations are also considered. Results indicate that AKR decays more slowly under loss‐only conditions, while PDR analysis shows higher key rates produce more concentrated distributions. These findings demonstrate the potential of PM‐MDI QKD protocols for achieving reliable key rates in satellite‐based quantum communication.