  The six-fold rotational symmetry of photonic crystal fibers has important
manifestations in the radiated fields in terms of i) a focusing phenomena at a
finite distance from the end-facet and ii) the formation of low-intensity
satellite peaks in the asymptotic far field. For our study, we employ a surface
equivalence principle which allows us to rigorously calculate radiated fields
starting from fully-vectorial simulations of the near field. Our simulations
show that the focusing is maximal at a characteristic distance from the
end-facet. For large-mode area fibers the typical distance is of the order 10
Lambda with Lambda being the pitch of the triangular air-hole lattice of the
photonic crystal fiber.
