Mainz 2017 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 2: Quantum Communication I
Q 2.3: Vortrag
Montag, 6. März 2017, 15:15–15:30, P 3
Time-Frequency Quantum Key Distribution Over Free Space — •Fabian Beutel1,2, Jasper Rödiger1,2, Nicolas Perlot1, Ronald Freund1, and Oliver Benson2 — 1Fraunhofer Heinrich Hertz Institute, Einsteinufer 37, 10587 Berlin, Germany — 2Humboldt-Universität zu Berlin, AG Nanooptik, Newtonstraße 15, 12489 Berlin, Germany
Quantum key distribution (QKD) enables the creation of a common secret key between two remote parties that are connected by a quantum channel. In the time-frequency (TF)-QKD scheme, Alice encodes her bits either in the arrival time (Pulse Position Modulation) or in the center frequency (Frequency Shift Keying) of weak laser pulses. Due to the time-frequency uncertainty relation, an eavesdropper can only extract limited information from intercepting these pulses. As with the traditional BB84 QKD scheme, post processing allows for the distillation of a secret key.
We have successfully implemented the TF-QKD scheme by using mostly off-the-shelf telecom components and avalanche photodiodes operating at 1550 nm. With our setup we achieve secret-key rates of more than 400 kbit/s back-to-back and 80 kbit/s over a 25 km fiber spool. Furthermore, we have tested our scheme over an outdoor free-space test range of 390 m in the Berlin city center and are currently in the process of extending it to longer outdoor test ranges.