TY  - JOUR
A1  - van Loock, Peter
A1  - Alt, Wolfgang
A1  - Becher, Christoph
A1  - Benson, Oliver
A1  - Boche, Holger
A1  - Deppe, Christian
A1  - Eschner, Jürgen
A1  - Höfling, Sven
A1  - Meschede, Dieter
A1  - Michler, Peter
A1  - Schmidt, Frank
A1  - Weinfurter, Harald
T1  - Extending Quantum Links: Modules for Fiber‐ and Memory‐Based Quantum Repeaters
JF  - Advanced Quantum Technologies
N2  - Elementary building blocks for quantum repeaters based on fiber channels and memory stations are analyzed. Implementations are considered for three different physical platforms, for which suitable components are available: quantum dots, trapped atoms and ions, and color centers in diamond. The performances of basic quantum repeater links for these platforms are evaluated and compared, both for present‐day, state‐of‐the‐art experimental parameters as well as for parameters that can in principle be reached in the future. The ultimate goal is to experimentally explore regimes at intermediate distances—up to a few 100 km—in which the repeater‐assisted secret key transmission rates exceed the maximal rate achievable via direct transmission. Two different protocols are considered, one of which is better adapted to the higher source clock rate and lower memory coherence time of the quantum dot platform, while the other circumvents the need of writing photonic quantum states into the memories in a heralded, nondestructive fashion. The elementary building blocks and protocols can be connected in a modular form to construct a quantum repeater system that is potentially scalable to large distances.
KW  - color centers
KW  - quantum communication
KW  - quantum dots
KW  - quantum repeaters
KW  - trapped atoms/ions
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228322
VL  - 3
IS  - 11
ER  - 
TY  - JOUR
A1  - Rau, Markus
A1  - Heindel, Tobias
A1  - Unsleber, Sebastian
A1  - Braun, Tristan
A1  - Fischer, Julian
A1  - Frick, Stefan
A1  - Nauerth, Sebastian
A1  - Schneider, Christian
A1  - Vest, Gwenaelle
A1  - Reitzenstein, Stephan
A1  - Kamp, Martin
A1  - Forchel, Alfred
A1  - Höfling, Sven
A1  - Weinfurter, Harald
T1  - Free space quantum key distribution over 500 meters using electrically driven quantum dot single-photon sources-a proof of principle experiment
JF  - New Journal of Physics
N2  - Highly efficient single-photon sources (SPS) can increase the secure key rate of quantum key distribution (QKD) systems compared to conventional attenuated laser systems. Here we report on a free space QKD test using an electrically driven quantum dot single-photon source (QD SPS) that does not require a separate laser setup for optical pumping and thus allows for a simple and compact SPS QKD system. We describe its implementation in our 500 m free space QKD system in downtown Munich. Emulating a BB84 protocol operating at a repetition rate of 125 MHz, we could achieve sifted key rates of 5-17 kHz with error ratios of 6-9% and g((2))(0)-values of 0.39-0.76.
KW  - QKD
KW  - electrically driven
KW  - free space
KW  - quantum dots
KW  - quantum key distribution
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-116760
VL  - 16
IS  - 043003
ER  -