Abstract
Continuous-variable quantum key distribution (CV-QKD) protocols based on coherent detection have been studied extensively in both theory and experiment. In all the existing implementations of CV-QKD, both the quantum signal and the local oscillator (LO) are generated from the same laser and propagate through the insecure quantum channel. This arrangement may open security loopholes and also limit the potential applications of CV-QKD. In this paper, we propose and demonstrate a pilot-aided feedforward data recovery scheme which enables reliable coherent detection using a "locally" generated LO. Using two independent commercial laser sources and a spool of 25 km optical fiber, we construct a coherent communication system. The variance of the phase noise introduced by the proposed scheme is measured to be 0.04 (rad^2), which is small enough to enable secure key distribution. This technology also opens the door for other quantum communication protocols, such as the recently proposed measurement-device-independent (MDI) CV-QKD where independent light sources are employed by different users.
Highlights
Quantum key distribution (QKD) allows two authenticated parties, normally referred to as Alice and Bob, to generate a secure key through an insecure quantum channel controlled by an eavesdropper, Eve [1,2,3,4,5]
The variance of the phase noise introduced by the proposed scheme is measured to be 0.04, which is small enough to enable secure key distribution. This technology opens the door for other quantum communication protocols, such as the recently proposed measurement-device-independent Continuous-variable quantum key distribution (CV-QKD), where independent light sources are employed by different users
All existing implementations of CV-QKD based on coherent detection contain a serious weakness: To reduce the phase noise, both the signal and the local oscillator (LO) are generated from the same laser and propagate through the insecure quantum channel [11,12,16,17]
Summary
Quantum key distribution (QKD) allows two authenticated parties, normally referred to as Alice and Bob, to generate a secure key through an insecure quantum channel controlled by an eavesdropper, Eve [1,2,3,4,5]. All existing implementations of CV-QKD based on coherent detection contain a serious weakness: To reduce the phase noise, both the signal and the LO are generated from the same laser and propagate through the insecure quantum channel [11,12,16,17]. We solve the above long-outstanding problem by proposing and demonstrating a pilot-aided feedforward data recovery scheme, which enables reliable coherent detection using a “locally” generated LO This scheme is built upon the observation that in the GMCS QKD, Bob does not need to perform the measurement in the “correct basis.”.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
