Optical solitons in the presence of second-order and third-order dispersion

Abstract

Recently, there has been a great deal of interest in soliton propagation in single-mode fibers. The equation governing the motion of the pulse envelope can be written in the following normalized form: where α and β are coefficients of the second-order and third-order dispersion, respectively. When β = 0, Eq. (1) is reduced to the nonlinear Schrodinger equation which supports bright soliton propagation in the anomalous dispersion region and dark soli ton propagation in the normal dispersion region. In practice, it is desirable to operate the system near the zero dispersion wavelength because of the lower power requirement there. As a result, the effect of third-order dispersion cannot be neglected. In this paper we show that solitons exist for Eq. (1) even for large values of β. Moreover, bright solitons exist at the normal dispersion as well as anomalous dispersion region. The mini mum power required for the soliton in the normal dispersion region is found to be lower than that in the anomalous dispersion region.