Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 67: Quantum Information: Quantum Communication II
Q 67.4: Talk
Friday, March 27, 2015, 11:45–12:00, K/HS1
Design and evaluation of a handheld Quantum Key Distribution sender module — •Gwenaelle Mélen1,2, Markus Rau1, Lukas Fuchs1, Giacomo Corrielli3, Henning Weier2, Sebastian Nauerth2, Andrea Crespi3, Roberto Osellame3, and Harald Weinfurter1,4 — 1Fakultät für Physik, Ludwig-Maximilians-Universität, 80799 München, Germany — 2qutools GmbH, 81371 München, Germany — 3Dipartimento di Fisica, Politecnico di Milano, and Istituto di Fotonica e Nanotecnologie (IFN-CNR), 20133 Milano, Italy — 4Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
Complementary to long distance Quantum Key Distribution (QKD) schemes, secure short-distance communication could also benefit daily-life applications such as banking. The design of our free-space QKD add-on for mobile devices allows to generate a secure key, e.g. at an ATM, for future online authentication or direct transaction.
The ultra-flat architecture (25× 2 × 1 mm) includes an array of four attenuated VCSELs with uniform emission properties at 850 nm. 100 ps pulses with low degree of polarization are produced at 100 MHz repetition rate. Four wire-grid polarizers fabricated using Focused Ion Beam Milling and exhibiting extinction ratios up to 29 dB control the qubit states. The polarized beams are spatially overlapped in a low-birefringence, single-mode waveguide array with one main output manufactured via femtosecond laser micromachining. An Android App controls the driving electronics and establishes a classical Wi-Fi channel with the receiver to provide full QKD functionality.