Small amplitude solitons on a pedestal in the modified nonlinear Schrödinger equation for negative index materials

We analyze the existence of small amplitude solitons on the background of a continuous wave in negative index materials by establishing an interesting connection between the modified nonlinear Schrödinger equation and Korteweg–de Vries equation. It is shown that the dynamical equation for modulated short pulses admits a novel small amplitude soliton solution analytically and which propagate in the negative index medium. We also examine the influence of nonlinear dispersion terms over the modulation instability windows arising in a modified nonlinear Schrödinger equation pertaining to negative index materials using well established semi-analytics called linear stability analysis. Gain spectrum investigation has been carried out for both anomalous and normal dispersion regimes