  In a three-level atomic system coupled by two equal-amplitude laser fields
with a frequency separation 2$\delta$, a weak probe field exhibits a
multiple-peaked absorption spectrum with a constant peak separation $\delta$.
The corresponding probe dispersion exhibits steep normal dispersion near the
minimum absorption between the multiple absorption peaks, which leads to
simultaneous slow group velocities for probe photons at multiple frequencies
separated by $\delta$. We report an experimental study in such a
bichromatically coupled three-level $\Lambda$ system in cold $^{87}$Rb atoms.
The multiple-peaked probe absorption spectra under various experimental
conditions have been observed and compared with the theoretical calculations.
