Free-space optics is a telecommunications technique which is already being used
for everyday exchange of information and has many advantages over other
techniques (bandwidth, low cost, mobility of the equipment, security, etc.);
within the next decade, it is likely to become an integral and essential part of
data-processing architectures and telecommunications.
A history of wireless optical telecommunications is given, together with a
recapitulation of the application of the principles of electromagnetism to
free-space optics. Coverage is also given to the transmitters and receivers of
optical beams, which are the basis of any optical communication system. These
devices were responsible for the first truly significant advances in the
performance of