Real-world two-photon interference and proof-of-principle QKD immune to detector attacks

We demonstrate, for the first time, controlled two-photon interference and Bell-state measurements between independent sources over 18 km of fiber deployed across Calgary. With this we demonstrate a new quantum key distribution protocol, up to 80 kms, that requires BSMs and provides security against any detector attack. Our demonstration removes a remaining obstacle for quantum communication, quantum repeaters and quantum networks.