Equivalent step-index model of multifilament core fibers

The accuracy of the recently presented 1 equivalent step index approximation of multifilament core fibers is analyzed in terms of the effective refractive index, mode field area and bending losses of the fundamental mode. A modified Vparameter for this class of fibers as well as a single-mode condition is proposed. By comparison with a full-vectorial finite element method it is shown that the relative deviation of the effective refractive index and the mode field area are in the magnitude of 1 %. No significant decrease of bending losses is found for multifilament core fibers.