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Experimental Quantum Key Distribution with Decoy States

2006; American Physical Society; Volume: 96; Issue: 7 Linguagem: Inglês

10.1103/physrevlett.96.070502

1092-0145

Yi Zhao, Bing Qi, Xiongfeng Ma, Hoi-Kwong Lo, Li Qian,

Quantum Computing Algorithms and Architecture

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.