I am new to the fiber-optic communication systems, and in reading some relevant papers, I faced to the term "span length" (such as long-span link) which I cannot distinguish it from the length of the cable.
For example in one of the figures, it has depicted a quantity for various spaning lengths vs. the length of the cable.
Can anyone explain what is the "span length" of a fiber-optic link? I surfed the internet, but did not get any answer.
In this context, a span is the cable length between two amplifying stations.
Fibre optic cables are fairly lossy. As such a signal can only be transmitted so far down a piece of "glass" before they must be received by a transceiver or relay device that decodes the optical signal, regenerates it and transmits it out again. This is a span.
The "cable length" itself could go from north America to Europe. A span may be only a kilometer.
ADDITION: That does not only apply to fibre-optics though. Any high frequency communication system, other than point to point micro-wave, needs the same "pass-the-bucket" handling.
Span in a ADSS cable is the aerial distance between two poles or towers, meaning the physical resistance of the jacket to support its own weight
