Entanglement Distribution and Teleportation in Assisted and Scalable Quantum Access Networks

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.