Dark optical solitons: physics and applications

We present a detailed overview of the physics and applications of optical dark solitons: localized nonlinear waves (or 'holes') existing on a stable continuous wave (or extended finite-width) background. Together with the traditional problems involving properties of dark solitons of the defocusing cubic nonlinear Schrodinger equation, we also describe recent theoretical results on optical vortex solitons; ring dark solitons: polarization domain walls; parametric dark solitons in a dispersive chi((2)) medium; vector dark solitons, coupled dark-bright soliton pairs, and we discuss the instability-induced dynamics of dark solitons in the models of generalized (i.e, non-Kerr) optical nonlinearities. Special attention is paid to the experimental demonstrations of temporal dark solitons in optical fibres and spatial dark solitons, especially dark-soliton stripes and vortex solitons, in a defocusing bulk medium. (C) 1998 Elsevier Science B.V. All rights reserved.