Abstract: An Entangled photons distribution and measurement system includes a photon source including two outputs, able to generate a pair of entangled photons, the first photon being emitted on the first output and the second photon on the second output, a first optical link connected to the first output of the photons source, to deliver the entangled photons to a first device, an optical switch to route photons from the second output of the photons source to the first or second output of the optical switch, a second optical link connected to the first output of the optical switch, to deliver the entangled photons to a second device, and a measurement device connected to the second output of the optical switch, wherein the optical switch is configured to switch between its first and second output to switch between two operating modes.