Tunable Femtosecond Soliton Propagation in Optical Fibers

We achieve a tunable femtosecond soliton solution of the extended nonlinear Schrodinger (ENLS) equation. Such a soliton can stably propagate in an optical fiber with negative third-order dispersion (β₀< 0) and it would not collapse even if the fiber loss is considered. All of these show that it is possible to realize the femiosecond soliton propagation in special optical fibers. Besides, it will be applied that the group velocity of the soliton varies with its intensity in some measurements.