Weak interaction for higher-order nonlinear Schrödinger equation: An application of soliton perturbation

•A similar analysis has been done for the scaler NLS equation but the analysis presented here is more rigorous.•We have found more scenarios for weak interaction of two single solitons for the higher-order NLS equation than the studies on the weak interaction for the scaler NLS equation. Using soliton perturbation theory, we analytically study weak interaction for a higher-order nonlinear Schrödinger equation. An ansatz consists of two well-separate single solitons is considered and slow variation of solitons parameters are found. Twelve different scenarios for when the initial velocities are zero are observed. A good comparison is found between numerical and analytical results.