The asymmetric dual-core fiber(ADCF)is proposed to obtain large group velocity dispersion(GVD)because of the coupling effects between the fundamental modes of the central core and high-order modes of the side core.The super-modes of the ADCF can provide anomalous-and normal-GVD profiles with large peak values at the maximum disper-sion wavelengths.The maximum dispersion wavelengths can be shifted in the wavelength window of 1 550 nm by properly tuning the refractive indexes and diameters of the cores or spacing between the two cores.Furthermore,the numerical results show that the ADCF with the normal-GVD supermode 1 can be employed in the pulse broadening,where the broadening factor can reach more than 30 without pulse distortion from nonlinear effects.