We demonstrate the quantum confined Stark effect near 1.5 μm in the InGaAs/AlGaAs quantum wells grown on GaAs. This is achieved through the successful growth of very highly mismatched InGaAs/AlGaAs multiple quantum wells (MQWs) on GaAs substrates by molecular beam epitaxy. In these devices, linearly graded InGaAs buffer layers are grown beneath the MQWs to minimize threading dislocations. Furthermore, to improve the material quality and interface smoothness of the MQWs, a very low growth temperature (280 °C) is used in addition to a one monolayer deposition of GaAs and growth interruptions on both sides of quantum wells. These devices clearly exhibit the quantum confined Stark effect as measured by electroabsorption at 300 K.