  We measured absorption spectra of T-shaped quantum wires at room temperature
using waveguide-transmission spectroscopy. Strong and narrow room-temperature
one-dimensional-exciton absorption peak was observed, which shows peak modal
absorption coefficient of 160 cm$^{-1}$ per 20 wires with $\Gamma$-factor of
$4.3\times10^{-3}$, width of 7.2 meV, and strong polarization anisotropy.
