Contributions to free-space optical communications: feasibility of utilizing Cherenkov telescopes as receivers and beam-wander correction in quantum communications

Abstract

This thesis focuses on the two main applications where free-space optical communication (FSOC) can bring the most significant impact: interplanetary communications and quantum communications. Consequently, the dissertation is structured in two sections. In the first one, a novel proposal is suggested regarding to using Cherenkov telescopes as ground-station receivers. A feasibility study addresses the posibility of using the technology developed for the gamma-ray telescopes that will make up the Cherenkov Telescope Array (CTA) in the implementation of a new kind of ground station. Among the main advantages that these telescopes provide are the much larger apertures needed to overcome the power limitation that ground-based gamma-ray astronomy and deep-space optical communication both have. Also, the large number of big telescopes that will be built for CTA will make it possible to reduce unitary costs by economy-scale production. The second section of the thesis is framed in the field of free-space Quantum Key Distribution (QKD), which has become a new paradigm in the discipline of information security. This technique offers a theoretically-secure way to communicate over an insecure channel since the presence of an eventual eavesdropper can be detected. The main challenge of Free-space QKD is the need to operate both under strong atmospheric turbulence and daylight background noise. To mitigate these effects, a trade-off is usually required when designing the receiver's optics, since a narrow field-of-view improves background noise rejection, but increases turbulence-related losses and a wide field-of-view produces the opposite effect. A correction system for atmospheric turbulence is proposed to overcome both limitations at the same time, and different strategies are analyzed and experimented to carry out the implementation and integration within the QKD system.

296 pages, in Spanish, 221 figures. PhD thesis (Carlos III University of Madrid / Spanish National Research Center), June 2015

References in corpus (22)

• Free-Space distribution of entanglement and single photons over 144 km
• Provably Secure and Practical Quantum Key Distribution over 307 km of Optical Fibre
• Wide field aplanatic two-mirror telescopes for ground-based gamma-ray astronomy
• Feasibility of 300 km Quantum Key Distribution with Entangled States
• Feasibility of free space quantum key distribution with coherent polarization states
• MAGIC upper limits on the very high energy emission from GRBs
• Studying Free-Space Transmission Statistics and Improving Free-Space QKD in the Turbulent Atmosphere
• The TACTIC atmospheric Cherenkov Imaging telescope
• Novel Photo Multiplier Tubes for the Cherenkov Telescope Array Project
• Status of the technologies for the production of the Cherenkov Telescope Array (CTA) mirrors
• Low-Impact Air-to-Ground Free-Space Optical Communication System Design and First Results
• CTA simulations with CORSIKA/sim_telarray
• The next generation Cherenkov Telescope Array observatory: CTA
• Dielectric Coatings for IACT Mirrors
• Open-structure composite mirrors for the Cherenkov Telescope Array
• The ASTRI SST-2M Prototype: Structure and Mirror
• SST-GATE: A dual mirror telescope for the Cherenkov Telescope Array
• V-shape liquid crystal-based retromodulator air to ground optical communications
• Mechanics and cooling system for the camera of the Large Size Telescopes of the Cherenkov Telescope Array (CTA)
• The Formation of Condensation on Cherenkov Telescope Mirrors
• Developments for coating, testing, and aligning Cherenkov Telescope Array mirrors in Tübingen
• Calibration of the ASTRI SST-2M Prototype using Muon Ring Images