Online ISSN:1349-8606
Progress in Informatics  
No.8 March 2011  
Page 57-63 PDF(1,134KB) | References
Passive preparation of BB84 signal states with coherent light
Marcos CURTY1, Xiongfeng MA2, Hoi-Kwong LO3 and Norbert LÜTKENHAUS4
1ETSI Telecomunicación, University of Vigo, Spain
2,4Institute for Quantum Computing, University of Waterloo, Canada
3Center for Quantum Information and Quantum Control, University of Toronto, Canada
(Received: October 30,2010)
(Revised: December 20,2010)
(Accepted: December 27,2010)
In a typical optical implementation of the Bennett-Brassard 1984 (so-called BB84) quantum key distribution protocol, the sender uses an active source to produce the required signal states. While active state preparation of BB84 signals is a simple and elegant solution in principle, in practice passive state preparation might be desirable in some scenarios, for instance, in those experimental setups operating at high transmission rates. Passive devices usually involve parametric down-conversion. Here we show that coherent light is also suitable for passive generation of BB84 signal states. Our method does not require any externally-driven element, but only linear optical components and photodetectors. The resulting key rate is similar to the one delivered by an active source.
Quantum key distribution, quantum communication, quantum-state engineering, passive transmitter
PDF(1,134KB) | References

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