Chee Tiong Ong

Numerical Solution of the Gardner Equation

The Gardner equation is commonly used to describe wave propagation in weakly nonlinear dispersive medium. The Gardner equation has a higher order nonlinear term, which could make the numerical calculation inaccurate. In this paper, the Gardner equation is solved using two numerical methods, i.e., the method of lines and pseudospectral method. The efficiency and accuracy of both methods were studied. Our results show that both methods are accurate and efficient methods to solve the Gardner equation. By comparing the accuracy of both the methods, the method of lines performs better than pseudospectral method most of the time.

Optical Soliton Simulation in Optical Fibers by OptiSystem

Fiber optic communication is often known to offer higher frequency transmission of signals with greater bit rate and larger data carrying capacity over a long distance with lower loss and interference as compared to copper wire electrical communication. However, several factors that would affect the performance of an optical fiber transmission are such as group velocity dispersion (GVD), fiber loss and also self-phase modulation (SPM). In this paper, the effects of GVD, SPM, optical soliton formation and fiber loss are simulated using OptiSystem 14. It is found that GVD broaden pulse in temporal domain without modifying its spectrum. Meanwhile, SPM creates chirp in spectrum with its temporal profile maintained. This work concluded that a balance between the GVD and SPM is essential to form solitonthat is able to travel for a long distance without being distorted. It is also found that the decrease in the amplitude of the soliton is dependent on the fiber loss and this decay in the signal increases with the propagation distance.

Numerical simulation of undular bore evolution with Chezy friction

This paper studies and simulates numerically the evolution of undular bore under the effect of damping in the framework of the perturbed extended Korteweg-de Vries equation. Here, we consider Chezy frictional term to be the damping term in the perturbed extended Korteweg-de Vries equation. Numerical simulations show that under the influence of the friction, the undular bore with thick leading wave will transform into KdV-like solitary wave as the leading wave of the undular bore. The amplitude of the “thick” leading wave will remain the same for some time even though there is dissipation effect.

Crank-Nicolson implicit method for the nonlinear Schrodinger equation with variable coefficient

In the present work, the Crank-Nicolson implicit scheme for the numerical solution of nonlinear Schrodinger equation with variable coefficient is introduced. The Crank-Nicolson scheme is second order accurate in time and space directions. The stability analysis for the Crank-Nicolson method is investigated and this method is shown to be unconditionally stable. The numerical results obtained by the Crank-Nicolson method are presented to confirm the analytical results for the progressive wave solution of nonlinear Schrodinger equation with variable coefficient.