Through computer simulation, the compression of bright optical pulses by dark solitons in the normal group-velocity dispersion region of single-mode fibers is analyzed both qualitatively and quantitatively. The results show that the compression ratio and compressed peak power of the bright pulse depend upon the initial relative peak power of the dark pulse to the bright pulse. The higher the initial relative peak power is, the higher the compression ratio and compressed peak power of the bright pulse are. We found that, for given initial conditions, there exists an optimum fiber length at which the width of the compressed bright pulse is minimum and that the optimum fiber length decreases with the initial relative peak power.