Recently

much attention has been focus on the investigation of the electroabsorption in the GaAs/AlGaAs quantum wells (QW's) because of its possibility of designing new types of electro-optic modulators. Much optical properties of the single QW's with different potential has been and being investigated experimently and theoriticaly with different methods. In these few years

the double quantum wells (DQWs) became the focus of the research. In this paper

by using the density matrix formalism and iterated method

the first-and the third-order intersubband optical absorption of double quantum well with infinit boundary was investigated theoretically. Thereafter

a typical GaAs/AlGaAs DQWs is presented to get the results. The results show that the peak absorption varies with the width of the intermediate potential barrier. And it also shows that the absorption decrease as the incident optical intensity increasing.