Soliton solutions of higher-order nonlinear schrodinger equation (NLSE) and nonlinear kudryashov's equation

This article secures new soliton solutions of the higher-order nonlinear Schrodinger equation (NLSE) and the nonlinear Kudryashov's equation by means of two analytical techniques, namely the extended (G'/G(2))-expansion method and the first integral method. Many exact traveling wave solutions such as hyperbolic function solutions, trigonometric function solutions and rational function solutions with free parameters are characterized. Periodic solitons, dark solitons, singular solitons, combo solitons and plane waves are obtained. The existence criteria for such solutions are also provided. Moreover, the modulation instability analysis is used to examine the stabilities of both equations, by which the modulation instability gain spectrums of both equations are obtained. The obtained solutions are also presented graphically.