Passive Optical Network Approach to GigaHertz-Clocked Multiuser Quantum   Key Distribution
  We present the application of quantum key distribution technologies to fiber-based broadband passive optical access networks. This application is based on our 850 nm wavelength gigahertz clock-rate single-receiver system, is compatible with existing telecommunications fiber and exploits a wavelength band not currently utilized in access networks. The developed quantum key distribution networks are capable of transmitting over distances consistent with the span of access links for metropolitan networks (10 km), at clock frequencies ranging up to 3 GHz. 
Veronica Fernandez, Robert J. Collins, Karen J. Gordon, Paul D.   Townsend, and Gerald S. Buller