Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 50: HL Poster IV

HL 50.7: Poster

Thursday, March 15, 2018, 19:00–21:00, Poster B

Receiver Module for Free-Space Single-Photon QKD using Solid-State Quantum-Light Sources — •Timm Kupko, Stephan Reitzenstein, and Tobias Heindel — Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Germany

High modulation bandwidth and high purity of single-photon states make InAs/GaAs based quantum dots an ideal light source for free space quantum-key-distribution (QKD) [1]. For such systems, we developed a receiver module with passive basis choice for polarization-encoded QKD via the BB84 protocol. The module consists of off-the-shelf optics, four APD detectors and time-tagging electronics.
Many attacks are known for trusted-device QKD systems. With this knowledge, we investigate the susceptibility of our receiver for spatial-side-mode channel attacks [2][3], a subgroup of faked state attacks exploiting detection efficiency mismatches.
We conduct experiments to estimtate the influence of the angle of incidence on the detection efficiencies and how countermeasures like spatial filtering can prevent such attacks.

[1] T. Heindel et al., New J. Phys. 14, 083001 (2012)

[2] M. Rau et al., IEEE J. Quantum Electron. 21, 660905 (2015)

[3] S. Sajeed el al., Phys. Rev. A 91, 062301 (2015)