Free Space Optical Communications, is a way of transmitting data, using light.
Free Space Optical Communications, is commonly abbreviated to FSO Communications.
FSO differs from the more commonly used Fibre Optic Cables, in that data travels through the air.
Traditional Fibre Optic technology uses strands of glass or plastic fibre, to direct the light source, containing the data.
FSO communications uses invisable and harmless ultraviolet light beams.
The highly focussed beams of light, have a number of advantages, compared with RF (Radio Frequency) Communications.
Advantages
FSO Communications offer greater data security, than RF based systems.
RF systems emit radio waves, which can easily be intercepted.
FSO uses a very narrow beam of light, which is hard to intercept.
FSO also cannot be detected using a frequency Spectrum Analyser, making detection by eavesdroppers, hard.
Optical Communications, can deliver higher data rate transmission, than an RF based system.
Disadvantages
Optical systems, transmit in a highly directional manner.
Being directional, means that it is not suitable for mobile or multi user reception.
This contrasts with RF signals, which can easily be made to transmit to lots of users, simultaneously.