9. Glossary

Optical Cross Atmospheric Link (OCAL)

Optical link between two optical terminals, whose propagation channel consists entirely or partly of the earth's atmosphere. These links are generally disrupted by atmospheric turbulence, and it is often necessary to implement mitigating means at the optical terminals (e.g. adaptive optics) to close the link budget.

Optical Inter-Satellite Link (OISL)

Link between two optical terminals, each on a satellite. The propagation channel is made up of a vacuum in space, which has no impact on signal transmission apart from the natural divergence of the beam.

signal-to-noise ratio (SNR)

In telecommunications, power ratio between the part of the signal that represents information and the rest, which constitutes background noise. It is...