This work deals with a review of the possible principles and construction of the terrestrial optical wireless links and the
problematic of the proper photodiode and laser diode selection according to the wavelength dependent atmospheric
transmittance and the photodiode sensitivity. For the calculations we used the power balance equations and the catalog
values of the available laser diodes and detectors. For the most commonly used free space optical links, the laser diode
price and the maximum power are also considered.