  The Forster resonant energy transfer mechanism (FRET) is investigated in
optically driven and electrically gated tunnel coupled quantum dot molecules.
Two novel FRET induced optical signatures are found in the dressed excitonic
spectrum. This is constructed from exciton level occupation as function of pump
laser energy and applied bias, resembling a level anticrossing spectroscopy
measurement. We observe a redistribution of spectral weight and splitting of
the exciton spectral lines. FRET among single excitons induces a splitting in
the spatially-direct exciton lines, away from the anticrossing due to charge
tunneling in the molecule. However, near the anticrossing, a novel signature
appears as a weak satellite line following an indirect exciton line. FRET
signatures may also occur among indirect excitons, appearing as split indirect
lines. In that case, the signatures appear also in the direct biexciton states,
as the indirect satellite mixes in near the tunneling anticrossing region.
