title: Experimental quantum key distribution with decoy states.
abstract: To increase dramatically the distance and the secure key generation rate of quantum key distribution (QKD), the idea of quantum decoys--signals of different intensities--has recently been proposed. Here, we present the first experimental implementation of decoy state QKD. By making simple modifications to a commercial quantum key distribution system, we show that a secure key generation rate of 165 bit/s, which is 1/4 of the theoretical limit, can be obtained over 15 km of a telecommunication fiber. We also show that with the same experimental parameters, not even a single bit of secure key can be extracted with a non-decoy-state protocol. Compared to building single photon sources, decoy state QKD is a much simpler method for increasing the distance and key generation rate of unconditionally secure QKD.
authors.affiliation: Center for Quantum Information and Quantum Control, Department of Physics, University of Toronto, Ontario M5S 3G4, Canada.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.forename: Bing
authors.initials: B
authors.lastname: Qi
authors.forename: Xiongfeng
authors.initials: X
authors.lastname: Ma
authors.forename: Hoi-Kwong
authors.initials: HK
authors.lastname: Lo
authors.forename: Li
authors.initials: L
authors.lastname: Qian