Reducing the number of single-photon detectors in quantum-key-distribution networks by time multiplexing

We demonstrate a method to reduce the number of single-photon detectors (SPDs) required in multiparty quantum key distribution (QKD) networks by a factor of 2 by using detector time multiplexing (DTM). We implement the DTM scheme for an entanglement-based time-bin protocol and compare QKD results with and without DTM in our QKD network with four users. When small efficiency losses are acceptable, DTM enables cost-effective, scalable implementations of multiuser QKD networks.