Only the known integrable cases of the Kodama-Hasegawa higherorder nonlinear Schrödinger equation pass the Painlevé test. Recent results of Ghosh and Nandy add no new integrable cases of this equation. Being a true high-technology application of a mathematical object, the optical soliton in fiber optical lines of communications is an ideal carrier of information because the integrability of its...

Abstract In this paper we study the existence and linear stability of almost periodic solutions for a NLS equation on circle with external parameters. Starting from seminal result Bourgain in [15] quintic NLS, propose novel approach allowing to prove unified framework persistence finite infinite dimensional invariant tori, which are support desired solutions. The is given through rather abstrac...