A detailed experimental study of the optical properties of separation by implanted oxygen (SIMOX) substrates is performed using photoluminescence techniques. The photoluminescence properties of SIMOX substrates are compared with those of Si substrates. The silicon-on-insulator (SOI) layer is found to be free of any strain. High-quality SiGe quantum wells are grown on SOI using gas source molecular beam epitaxy. It is found that the photoluminescence properties of these quantum wells on SOI differ significantly from those of the SiGe quantum wells grown on a Si substrate under identical growth conditions. Intense photoluminescence and higher operation temperature are obtained for quantum wells grown on SOI substrates. It is shown that growth of a few hundred Å Si buffer layer on SOI is essential in order to achieve a high quality SiGe epitaxy on SOI. Finally, aSiO2/Si/SiO2optical cavity is proposed on SIMOX substrates, and it is employed to further enhance the photoluminescence intensity of SiGe quantum wells on SOI. ©1997 American Institute of Physics.