Finite cladding effects in W fibers: a new interpretation of leaky modes

Abstract

From recent experimental results, the usual fiber model with infinite outer cladding fails to give an accurate description of the mode behavior beyond cutoff. The finite dimensions of the actual fiber must be taken into account; the leaky mode formalism is then replaced with a theory of coupling between a core mode and discrete, lossy cladding modes. The excitation and attenuation of the modes resulting from this coupling are considered in some detail; this more realistic model allows a better agreement with experiment.