Properties of compact bright pulse in long optical waveguide: Higher-order effects

Abstract

The properties of the compact bright (CB) pulse propagating in the long optical waveguide under the action of third-order dispersion (TOD), time derivative of the pulse envelope and first moment of the nonlinear response function of the waveguide known as the Raman term are investigated. From the dispersionless nonlocal Nonlinear Schrodinger equation (NLS) describing the propagation of light beam in the waveguide with nearly instantaneous nonlinear response and extended either by the TOD or the time derivative of the pulse envelope, the exact analytical expressions of CB pulse are derived. It appears that although the TOD does not affect the pulse amplitude, shape and width, it induces the deviation of the pulse velocity from the group velocity of the wave packet with a magnitude depending of the pulse frequency. Similarly, the presence of the time derivative of the pulse envelope affects the pulse parameters namely the shape, width and constant of propagation and also induces the self-steepening of the CB pulse. As for the Raman term, the result from the perturbation approach shows that the CB pulse experiences a self-frequency shift linearly proportional to the distance of propagation of the pulse. Although some of the obtained results are qualitatively similar to those previously exhibited by the bright soliton, the analytical expressions are quite different. The accuracy of these analytical results is checked trough numerical simulations of the appropriated extended nonlocal NLS equation and the wave spectrum.