Ultrasolitons: multistability and subcritical power threshold from higher-order Kerr terms

TL;DR

This paper demonstrates that higher-order Kerr nonlinearities in optical systems can support ultrasolitons, which are highly localized modes appearing above a power threshold, coexisting with regular solitons and enabling multistability and soliton switching.

Contribution

It introduces the concept of ultrasolitons supported by higher-order Kerr effects, providing analytical conditions for multistability and analyzing their dynamics and transitions.

Findings

Ultrasolitons exist above a certain intensity threshold.

Ultrasolitons can coexist with lower-intensity solitons.

Multistability and soliton switching mechanisms are characterized.

Abstract

We show that an optical system involving competing higher-order Kerr nonlinearities can support the existence of ultrasolitons, namely extremely localized modes that only appear above a certain threshold for the central intensity. Such new solitary waves can be produced for powers below the usual collapse threshold, but they can also coexist with ordinary, lower-intensity solitons. We derive analytical conditions for the occurrence of multistability and analyze the dynamics of the different kinds of fundamental eigenmodes that can be excited in these nonlinear systems. We also discuss the possible transitions between solitary waves belonging to different nonlinear regimes through the mechanism of soliton switching.