Optical link
An optical link is a telecommunications link that consists of a single end-to-end optical circuit. A cable of optical fibers, possibly concatenated into a dark fiber link, is the simplest form of an optical link.
Other forms of optical link can include single-"colour" links over a wavelength division multiplex infrastructure, and/or links that use optical amplifiers to compensate for attenuation over long distances.
Other forms of optical links include free-space optical telecommunication links.
In the rail transport sector, optical links are used in two forms depending on whether the feeding station is a main station or not. Thus main stations are called 'long halls', and all remaining stations are said to be 'short halls'.
