We have investigated the entanglement distribution and quantum teleportation in quantum passive optical networks, where an entangled state is distributed between the central node and multiple end users through lossy fibers and passive optical splitter/combiner. The entanglement degradation is quantified using logarithmic negativity and teleportation fidelity, both in nonassisted and assisted strategies. We find that nonassisted teleportation fidelity rapidly drops below the classical limit as the number of users increases (possible up to five users), while assisted teleportation remains robust against both network size and photon loss, provided that the distributed entangled resource has sufficiently high fidelity. These results highlight the fundamental limitations of bipartite schemes and establish cooperative assisted strategies as essential primitives for scalable fiber-to-the-home quantum access networks and the quantum internet with several end users.
Amir Mohammad Yaghoobianzadeh, J. A. Salehi· IEEE Transactions on Quantum...· 1 citation
Introduction: Continuous-variable quantum teleportation and entanglement distribution are fundamental building blocks for future quantum internet infrastructures. Quantum passive optical networks (QPONs) provide a promising architecture for scalable multi-user quantum communication by exploiting the mature passive optical network infrastructure.
Materials and methods: We develop a theoretical framework for continuous-variable entanglement distribution and quantum teleportation in QPONs using two-mode squeezed vacuum states propagating through splitter–combiner–loss channels. Both downlink and uplink architectures are investigated under assisted and non-assisted protocols. The performance is analyzed using covariance matrix formalism, logarithmic negativity, and teleportation fidelity, and closed-form analytical expressions are derived together with numerical evaluations.
Results: The analysis demonstrates that downlink entanglement distribution consistently outperforms the uplink architecture in terms of both logarithmic negativity and teleportation fidelity except in noise-less channels. Assisted protocols further enhance the achievable performance compared with non-assisted schemes. We derive the optimum squeezing parameter for non-assisted teleportation, showing that excessive squeezing may become detrimental because of network loss and splitting. Numerical results quantify the effects of network size, transmission distance, channel excess noise, detector imperfections, and measurement-added noise on entanglement distribution and teleportation performance. Also, we have showed that the time-division multiple-access is the preferred scheduling scheme between the users.
Conclusions: The proposed framework establishes fundamental performance limits for continuous-variable QPONs and identifies practical design guidelines for scalable quantum access networks. The results demonstrate the advantages of downlink entanglement distribution and assisted teleportation, providing theoretical support for the development of future multi-user quantum communication and quantum internet infrastructures.
Amir Mohammad Yaghoobianzadeh, J. Salehi· Academia Quantum· 0 citations
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