“…Moreover, it is observed that QSCM and FDM mode solver have the same convergence rate. However, with the same grid size, namely the same amount of computation effort, QSCM mode solver is more accurate than conventional FDM mode solver [4,5], however, it should be addressed that the current QSCM loses the advantage comparing to the improved finite difference method [7,10,11] where higher order boundary conditions are applied. The improved QSCM with higher order boundary conditions will be our future work.…”