Abstract
We present theoretical calculations of optical absorption/gain spectra for condensed excitons in semiconductor quantum wells as functions of the electron-hole pair density and temperature. The ladder diagram contribution to the vertex function (exciton effect) is included in our calculation. Our studies show that the effects of exciton condensation on the absorption/gain spectra remain present for temperatures up to 130 K for a 2D ZnSe system and the exciton effects are important in determining the absorption/gain spectra.