Abstract

Dual-core fibres have been proposed as optical filters and (linear/nonlinear) switches in various optical systems [1,2]. In the case of nonlinear switches, the optical non-linearity of fused silica can be resonantly enhanced by doping the fibre cores with appropriate materials, such as erbium [3,4], resulting in a dramatic reduction of the switching power. The twin-core fibre geometry has also been utilised to implement a passive channel-equalising erbium-doped fibre amplifier. The device operation relies on this geometry-induced wavelength separation and the concomitant spatial “hole” burning [5-6].

© 1994 Optical Society of America