A long-throw, tight focussing optical coupler has a first passive optical element
capable of coupling light between an optical source and an optical destination
and a second passive optical element, capable of coupling light between the optical
source and the optical destination, located between the first passive optical element
and one of the optical source or the optical destination such that, a light beam
from the optical source will be transferred to the optical destination when the
optical source and optical destination are spaced apart by a distance.