Design and analysis of a multilayer cladding large-mode-area optical fibre

Abstract

We present a large-mode-area optical fibre design consisting of a multilayer cladding. Thecladding is formed by alternate high and low index regions specially designed to strip-off higher-order modes, while causing a nominal loss to the fundamental mode. The fibre is analysed by the transfer matrix method and the leakage losses of the modes are calculated. Ahigh differential leakage loss between the first two modes ensures single-mode operation. Withthe proposed design a fibre with 30νm core diameter and 0.16 numerical aperture can exhibit single-mode operation at 1550 nm wavelength. Such a large-core fibre can suppress the nonlinear effects and should be useful for high power applications, including fibre lasers and optical communication systems employing DWDM. © IOP Publishing Ltd.