Free-space Quantum Key Distribution: trucks, aircraft and satellites

Talk

Speaker: Thomas Jennewein
When: Sep. 11 2017 11:45
Where: Erwin Schrödinger Saal

Quantum Key Distribution between moving platforms is an important step towards realizing a secure network applicable to special use-cases in the field as well as for reaching global distances via quantum satellites. While free-space quantum communication is similar to fiber-optic systems, the intrinsically variable free-space quantum channel poses unique challenges, including the alignment of reference frames between Alice and Bob, optics design and telescopes with active pointing and tracking, blocking background signals and coping with atmospheric turbulence which makes the beams multi-modal. I will present our experimental results for transmitting polarization encoded quantum signals from a stationary transmitter to a moving quantum receiver located on a moving truck as well as the prototype satellite payload demonstrated on an aircraft. As a viable alternative to polarization encoding, I will present the recent achievements on implementing "field-widened time-bin analyzers" suitable for high interference visibility with highly multi-modal spatial and temporal photon beams. In conclusion, I will illustrate that time-bin encoding of photons is now applicable to highly multimodal beams, and could lead to interesting advances and applications for quantum communications not possible with polarization encoding.

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