Figure 1

(a) Communication layer of the four-user full-mesh network. Every pair of users share a bipartite entangled state as represented by each individual infinity symbol. (b) Physical layer of the network consists of a polarization-entangled photon source, q-ROADM (consisting of fibre polarization controllers (FPC), optical switch (OS), de-multiplexer DEMUX and multiplexer MUX) and polarization analysis module (PAM). Each user has a PAM consisting of a beamsplitter (BS), polarization beamsplitter (PBS), half waveplate (HWP), shutters (S), and mirrors. Single-photon detectors are depicted as D₁ and D₂. Solid lines depict optical fibres and dashed lines free-space path of photons