Flexible Cloud/User-Centric Entanglement and Photon Pair Distribution With Synthesizable Optical Router

Abstract

The practical roll-out of quantum communication technologies in optical networks and the adoption of novel quantum applications demand the distribution of single or entangled photons. Flexibility and dynamicity are paramount for the provision of quantum resources, in order to scale with the number of users and to meet the demand of complex network architectures. We present a quantum network architecture that features this degree of reconfigurability, without being restricted to a rigid physical-layer network based on purely passive multiplexing componentry. We leverage spectral assets of photon-pair sources, from the short-wavelength band to the L-band, and agile spatial switching at a remote optical network node, in order to realize a flexible distribution map that features different flavors, reaching from cloud-centric to user-centric quantum connectivity. Photon pair distribution is experimentally demonstrated between five users in a 17-km reach, tree-shaped optical network, with high visibility entanglement shared between three users of the network. Simultaneous distribution of photons to more than one user is enabled and the delivered photon rate can be dynamically adjusted. Penalty-free operation is confirmed for integrating a co-existing classical control channel within the quantum.