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This thesis focuses on the two main applications where free-space opticalcommunication (FSOC) can bring the most significant impact: interplanetarycommunications and quantum communications. Consequently, the dissertation isstructured in two sections. In the first one, a novel proposal is suggestedregarding to using Cherenkov telescopes as ground-station receivers. Afeasibility study addresses the posibility of using the technology developedfor 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 mainadvantages that these telescopes provide are the much larger apertures neededto overcome the power limitation that ground-based gamma-ray astronomy anddeep-space optical communication both have. Also, the large number of bigtelescopes that will be built for CTA will make it possible to reduce unitarycosts by economy-scale production. The second section of the thesis is framedin the field of free-space Quantum Key Distribution (QKD), which has become anew paradigm in the discipline of information security. This technique offers atheoretically-secure way to communicate over an insecure channel since thepresence of an eventual eavesdropper can be detected. The main challenge ofFree-space QKD is the need to operate both under strong atmospheric turbulenceand daylight background noise. To mitigate these effects, a trade-off isusually required when designing the receiver's optics, since a narrowfield-of-view improves background noise rejection, but increasesturbulence-related losses and a wide field-of-view produces the oppositeeffect. A correction system for atmospheric turbulence is proposed to overcomeboth limitations at the same time, and different strategies are analyzed andexperimented to carry out the implementation and integration within the QKDsystem.

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