The normal-mode coupling dispersive medium in a symmetric one-dimension photonic crystals(1D PCs)was studied.The frequency shift effect

homogeneous broadening effect

and the detuning effect of the normal coupled modes can be well controlled by adjusting the parameters of the dispersive medium.It is found that the separation between the two transmission peaks enlarges with increasing the dimensionless coupling strength.It implies that we can modulate the frequency shift of the dispersive defect by adjusting the parameter of the dispersive medium.The broadening effect of normal coupled modes is related to the reduced oscillator HWHM linewidth.Detuning effect of dispersive layer will make one peak rapidly drop and the other relatively much higher.It can be understood by Fabry-Pérot cavity analysis.