  Polarized far-infrared transmittance spectra of CuGeO_3 single crystals were
measured at different temperatures (6K < T < 300K). Two spectral lines, at
284.2 cm-1 in E||c polarization and at 311.7 cm-1 in E||b polarization, appear
at the temperature of the spin-Peierls transition and grow in intensity with
decreasing temperature. Both of them are, most probably, folded modes of the
dimerized lattice. We discuss a possible role of the spin-phonon interaction in
the formation of the 311.7 cm-1 feature.
