Five-user quantum virtual local area network with an AlGaAs entangled photon source

The promotion of quantum network applications demands the scalable connection of quantum resources. It is preferable to set up multiple logical networks coexisting on a single physical network infrastructure to accommodate a larger number of users. Here we present a quantum virtual network architecture that offers this level of scalability, without being constrained to a fixed physical-layer network relying solely on passive multiplexing components. The architecture can be understood as arising from the superposition of a fully connected entanglement distribution network and port-based virtual local area network, which group multiusers by access ports. In terms of hardware, we leverage a semiconductor chip with a high figure-of-merit modal overlap to directly generate high-quality polarization entanglement, and a streamlined polarization analysis module, which requires only one single-photon detector for each end user. We experimentally perform the BBM92 QKD protocol on the five-user quantum virtual network and demonstrate voice and image encryption on a campus area network. Our results may provide insights into the realization of large-scale quantum networks with integrated and cost-efficient photonic architecture.