Quantum Communications (QC) in Space are gaining a strong momentum for both providing the way to realize tests on the interplay of Quantum Physics and Gravity on very long scale and for terminals in relative motion as well as to provide a network of secure communications on planetary scale.

In the perspective to extend the realm of QC toward larger distances, we would like to present the extension of the single photons exchange, initially demonstrated for LEO orbits to a source in MEO orbit.

Moreover, we would like to report on the experiment using the temporal modes of light as the physical degree of freedom used for the encoding of the qubit. This represent an evolution with respect to the polarization of the photon, used in the first demonstration of QC in Space.

These Space QC experiments were realized at MLRO - Matera Laser Ranging Observatory of the ASI Italian Space Agency, in Matera, Italy.

References

- D. Rideout et al., Fundamental quantum optics experiments conceivable with satellites reaching relativistic distances and velocities, Classical and Quantum Gravity 29, 224011 (2012).

- P. Villoresi et al., Experimental verification of the feasibility of a quantum channel between space and Earth, New J. Phys. 10, 033038 (2008).

- G. Vallone et al, Experimental Satellite Quantum Communications, Phys. Rev. Lett. 115, 040502 (2015). Editors’ Suggestion. Viewpoint http://physics.aps.org/articles/v8/68. Selected as Highlight of the Year 2015, American Physical Society, http://physics.aps.org/articles/v8/126.

- D. Dequal et al. Experimental single photon exchange along a space link of 7000 km, Phys. Rev. A 93, 010301(R) (2016).

- G. Vallone et al. Quantum interference along satellite-ground channels, arXiv:1509.07855 (2015).