Optical solitons in a monomode fiber

We discuss the propagation of optical solitons in a monomode fiber as a model of long-distance-high-bit-rate transmission system. We give several new results which did not appear in our previous papers on this subject, such as (1) a derivation of the perturbed nonlinear Schrödinger equation from the Maxwell equation, (2) on the integrability of the perturbed nonlinear Schrödinger equation, (3) a discussion of the soliton as a stable fixed point of certain infinite-dimensional map generated by a transmission system with periodic excitations.On leave of absence from The Ohio State University, Department of Mathematics, Columbus, Ohio 43210.