Chiral Solitons To The Generalized Nonlinear Schr(?)dinger Equation

As optical pulse propagation in optical fibers, fibre dispersion causes optical pulse at different wavelengths travelling at different speeds in fiber, which is group-velocity dispersion(GVD), GVD makes pulse broadening in fiber. Nonlinear effect occurs in fiber when the optical intensity is great enough, which makes pulses compression. The GVD and nonlinear effect can cooperate in such a way that the optical pulse propagates stably as an optical soliton. Therefore, the distance and speed of the communication will be greatly increased. The law of optical pulse propagation in fiber is described by the nonlinear Schrodinger equation(NLSE), studying on solving the equation has important significance of studying. With the development of ultrashort and high-power optical pulse, higher-order effects such as third-order dispersion(TOD), self-steepening(SS) and self-frequency shift(SFS) play important roles in the pulse propagation, the NLSE should be modified to generalized nonlinear Schrodinger equation(GNLSE).In this paper, firstly, introduces the origin and development of the soliton, theoretical and practical significance on subject selection, basic principles of pulse propagation in fiber and some methods to look for the solutions of NLSE.Secondly, based on the GNLSE with TOD, SS, SFS and saturable nonlinear term, we obtain two chiral phase solitons to the equation. The numerical computation of the solitons show reversal across the curves. Studying on the public area of the two solitons, we get two kinds of curves which evolution in opposite direction for each component in the area, the curves bind with each other during the neighborhood of origin. It shows that the phase solitons have chiral character themselves, it has important sense to improve stability of optical pulse propagation in fiber.Finally, the paper also gives some curves of the phase solitons under the condition of different TOD values, demonstrating the process of chiral soliton. The reversal character of the chiral phase solitons disappear gradually when the value of the TOD decreases from positive to zero, solitons are remain chiral. When the value becomes negative, they are still chiral but switch evolution directions with each other.