Abstract

Event horizons (EHs) can be mimicked in optical fibers by the nonlinear interaction of a weak linear radiation (usually termed probe wave) with an intense soliton [1,2]. This occurs when the probe wave is partly or totally reflected on the soliton as a result of close but different group velocities (GV) inducing their collision. The soliton acts as a nonlinear barrier which modifies the group velocity of the probe wave and therefore results in its frequency conversion into an idler wave following a phase-matching (PM) condition [3]. Generally, this interaction is induced by launching two pulses (one is exciting a soliton and the other one is the probe) whose wavelengths and relative delay have to be carefully adjusted to induce their collision within the fiber. Here, we introduce a much simpler experimental scheme dedicated to the observation of EH. A single laser pulse is used to excite a soliton which generates itself a dispersive wave (DW) acting as the probe. Their collision is induced by longitudinally changing the dispersion properties of the fiber. The varying dispersion along the fiber not only reshapes the DW trajectory in the time domain, but it also modifies the PM condition, allowing the collision to occur at a distance where the PM condition is suitable for the observation of a fiber EH.

© 2015 IEEE