Extensible router for multi-user quantum key distribution network
  A feasible quantum key distribution (QKD) network scheme has been proposed with the wavelength routing. An apparatus called "quantum router", which is made up of many wavelength division multiplexers, can route the quantum signals without destroying their quantum states. Combining with existing point-to-point QKD technology, we can setup a perfectly QKD star-network. A simple characteristic and feasibility of this scheme has also been obtained. 
Tao Zhang, Zheng-Fu Han, Xiao-Fan Mo, and Guang-Can Guo