Dispersion relation equation preserving FDTD method for nonlinear cubic Schrodinger equation

In this study we aim to solve the cubic nonlinear Schrodinger (CNLS) equation by the method of fractional steps. Over a time step from t(n) to t(n+1), the linear part of the Schrodinger equation is solved firstly through four time integration steps. In this part of the simulation, the explicit symplectic scheme of fourth order accuracy is adopted to approximate the time derivative term. The second-order spatial derivative term in the linear Schrodinger equation is approximated by centered scheme. The resulting symplectic and space centered difference scheme renders an optimized numerical dispersion relation equation. In the second part of the simulation, the solution of the nonlinear equation is computed exactly thanks to the embedded invariant nature within each time increment. The proposed semi-discretized difference scheme underlying the modified equation analysis of second kind and the method of dispersion error minimization has been assessed in terms of the spatial modified wavenumber or the temporal angular frequency resolution. Several problems have been solved to show that application of this new finite difference scheme for the calculation of one- and two-dimensional Schrodinger equations can deemed conserve Hamiltonian quantities and preserve dispersion relation equation (DRE). (C) 2015 Elsevier Inc. All rights reserved.