A simple magnetic modulation structure of the exchange-coupling FePt/FeNi bilayer film is fabricated and studied for its magnetization dynamics using time-resolved magneto-optical polar Kerr spectroscopy.It is found that two spin-wave modes can be excited.One is fixed at ～3.2 GHz in frequency for any exteal field and may serve as a frequency-stabilized spin-wave filter,while the other is exteal field dependent.In contrast,only the exteal field-dependent mode is excited in single-layer FeNi,supporting the localized origin of the mode at ～3.2 GHz,which is confined to a thin exchange-coupling region.The other exteal field-dependent mode in frequency is attributed to the Kittel mode.