  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.
