45 research outputs found
Optical Free-Space Communication on Earth and in Space regarding Quantum Cryptography Aspects
No full textMobile FSO Communication links have gained signi�cant at-
tention over the last years due to their increasing maturity. They are used in point to point link scenarios where the high gain in power efficiency and datarate is crucial, compared to state-of-the-art RF links.
The Optical Communication Group of German Aerospace Center's Institute of Communication and Navigation is conducting research and practical investigations of mobile optical high-speed communication links between diverse platforms, e.g. optical links from aircrafts, UAVs or Satel-
lites to Ground.
This paper will give an overview on the current and future work of the Optical Communication Group in this fi�eld, with additional regard to quantum communications
Space-quest, experiments with quantum entanglement in space
No full textThe European Space Agency (ESA) has supported a range of studies in the field of quantum physics and quantum information science in space for several years, and consequently we have submitted the mission proposal Space-QUEST (Quantum Entanglement for Space Experiments) to the European Life and Physical Sciences in Space Program. We propose to perform space-to-ground quantum communication tests from the International Space Station (ISS). We present the proposed experiments in space as well as the design of a space based quantum communication payload
Free-space quantum key distribution over 144 km
No full textWe report on the experimental implementation of a BB84-type quantum key distribution protocol over a 144 km free-space link using weak coherent laser pulses. The security was assured by employing decoy state analysis, and optimization of the link transmission was achieved with bi-directional active telescope tracking. This enabled us to distribute a secure key at a rate of 11 bits/s at an attenuation of about 35 dB. Utilizing a simple transmitter setup and an optical ground station capable of tracking spacecraft in low earth orbit, this outdoor experiment demonstrates the feasibility of global key distribution via satellites
Entanglement-based quantum communication over 144km
No full textQuantum entanglement is the main resource to endow the field of quantum information processing with powers that exceed those of classical communication and computation. In view of applications such as quantum cryptography or quantum teleportation, extension of quantum-entanglement-based protocols to global distances is of considerable practical interest. Here we experimentally demonstrate entanglement-based quantum key distribution over 144km. One photon is measured locally at the Canary Island of La Palma, whereas the other is sent over an optical free-space link to Tenerife, where the Optical Ground Station of the European Space Agency acts as the receiver. This exceeds previous free-space experiments by more than an order of magnitude in distance, and is an essential step towards future satellite-based quantum communication and experimental tests on quantum physics in space
Methodology for Traffic Analysis and ISL Capacity Dimensioning in Broadband Satellite Constellations Using Optical WDM Networking
No full textBidirectional 20-Gbit/s OOK Link with a 4-Telescope Array and Incoherent Signal Combining
No full textBidirectional 20-Gbit/s OOK Link with a 4-Telescope Array and Incoherent Signal Combining
No full textS.130-133We present experimental results on a bidirectional link between a telescope array and a single-telescope antenna. Each telescope is coupled to a single-mode fiber. A fine tracking mechanism equips each telescope. The array telescopes provide diversity channels with uncorrelated noises, in particular uncorrelated turbulence fluctuations and ASE noise. We apply signal combining with incoherent detection. The array is meant to be on ground whereas the single telescope terminal would typically be above the atmosphere. In the downlink, the 1545-nm beam is received by each array telescope, optically amplified, filtered, photodetected and digitized. In the uplink, The ITU grid channels 26, 27, 28 and 29 (100 GHz spacing) are emitted. BER is measured at 20 Gbit/s in both link directions over a 400m free-space test range in Berlin. We discuss the scalability of the telescope array for up- and down-links
