Unusual self-spreading or self-compression of the cubic-quintic NLSE solitons owing to amplification or absorption

Abstract

It is usually believed that solitons always expand due to absorption, and vice versa, they can be significantly compressed due to amplification. Contrary to this usual opinion, we demonstrate that the higher-order nonlinearity opens the possibility to observe unusual and contrasting effects, namely, the soliton self-spreading effect arising due to the soliton amplification and vise versa, the soliton self-compression effect appearing in the absorption regime of the soliton propagation. The detailed contrasting scenarios of the soliton self-spreading or self-compression owing to amplification or absorption are considered in the framework of the simplest cubic-quintic nonlinear Schrödinger equation model.