Compositionally modulated (Fe-Si)/Si amorphous films have been obtained by RF sputtering. Varying the thickness d_s of Si layers with a fixed thickness of the Fe-Si layers, it is found that, when d_s is smaller than a critical value, a strong-coupling effect between magnetic layers begins to occur. The results are that the low-hysteresis effect disappears, the saturation magnetization M_s and Curie temperature T_C increase monotonically with decreasing d_s, and perpendicular anisotropy appears. The experiments showed that M_s increases exponentially and T_C increases linearly with decreasing d_s because of the coupling effect.