System: free-space optical communication link
Optical space communications systems

A free space optics (FSO) link is a system for transporting information over a distance using an optical carrier in air or vacuum (unguided). It requires the use of two terminals, one transmitting (often called Tx) and the other receiving (often called Rx). It can be monodirectional (simplex) (figure 2 a) or bidirectional (duplex) (figure 2 b). In the latter case, each terminal is both transmitter and receiver. A duplex link can be full-duplex when it carries information simultaneously in both directions, or half-duplex when it alternates...