Real-World Proof-of-Principle Demonstration of Measurement-Device Independent Quantum Key Distribution

28 11/2013

Thursday, 28 Nov. 2013, 11:00 - 12:00

Workgroup Aspelmeyer Group

Presenter: Joshua Slater, University of Calgary, CAN
Host: M. Aspelmeyer
Where: Schrödingerzimmer, Boltzmanngasse 5, 4th floor, 1090 Wien

We demonstrate the feasibility of a new quantum key distribution protocol that provides security against any eavesdropping attack exploiting vulnerabilities of single photon detectors. MDI-QKD is a clever time-reversed version of QKD based on Bell-state measurements

(BSMs) between weak coherent pulses.  However, due to time-varying properties of optical fiber, significant changes to photon properties can occur in under a minute and destroy the indistinguishability required for a successful BSM.  Our demonstration thus controls all degrees-of-freedom and allow for controlled two-photon interference across real-world deployed fiber over 18 km in length (and over 100 km in the lab). Our MDI-QKD system is automated, deployable in the real-world, and, contains only off-the-shelf components; the robustness of which demonstrates MDI-QKD is a realistic technology for safe-guarding secrets during transmission. Finally, by demonstrating real-world BSMs, we have removed a remaining obstacle to building quantum repeaters, for quantum communication, and quantum networks.