Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking. "Free space" means air, outer space, vacuum, or something similar. This contrasts with using solids such as optical fiber cable.
An 8-beam free-space optics laser link, rated for 1 Gbit/s. The receptor is the large lens in the middle, the transmitters the smaller ones. At the top right corner is a monocular for assisting the alignment of the two heads.
A photophone receiver and headset, one half of Bell and Tainter's optical telecommunication system of 1880
WW I German Blinkgerät
DARPA ORCA official concept art created c. 2008
Optical wireless communications (OWC) is a form of optical communication in which unguided visible, infrared (IR), or ultraviolet (UV) light is used to carry a signal. It is generally used in short-range communication.
Illustration of the Laser Communications Relay Demonstration (LCRD) relaying data from ILLUMA-T on the International Space Station to a ground station on Earth.