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.