  The normal state optical response of La_{2-x}Sr_xCuO_4 is found to be
consistent with a simple multi-component model, based on free carriers with
strong electron-phonon interaction, localized polaronic states near 0.15 eV and
a mid-infrared band at 0.5 eV. Normal state reflectance and absorbance of
La_{1.83}Sr_{0.17}CuO_4 are investigated and their temperature dependence is
explained. Both, the ac and dc response are recovered and the quasi-linear
behavior of the optical scattering rate up to 3000- 4000 cm^{-1} is found to be
consistent with strong electron-phonon interaction, which also accounts for the
value of T_c. Although not strictly applicable in the superconducting state,
our simple model accounts for the observed penetration depth and the optical
response below T_c can be recovered by introducing a small amount of additional
carriers. Our findings suggest that the optical response of La_{2-x}Sr_xCuO_4
could be explained both, in the normal and superconducting state, by a simple
multi-fluid model with strong electron-phonon interaction if the gap symmetry
and the temperature dependence of the 0.5 eV mid-infrared band are adequately
taken into account.
