Field-Induced Optical Properties of Gallium Arsenide/aluminum Gallium Arsenide Multiple Quantum Well Waveguides

Linear and non-linear electro-absorption and electro -refraction associated with the multiple quantum well (MQW) material has been investigated by first designing a single mode optical waveguide which employs GaAs/AlGaAs MQWs in the core region and then carrying out the computer controlled experimental study over a wide range of photon energies below the exciton resonances. A direct method has been presented to estimate the change in refractive index ( Deltan) of the MQW as a function of electric field applied perpendicular to the MQW layers. In this method, the waveguide mode profile is observed with and without the applied electric field and the resulting change in mode shape has been used to calculate Deltan. The results are compared with the Deltan values calculated from the observed changes in the absorption coefficient ( Deltaalpha) through the Kramer's Kronig transformation. A good agreement between the results have been obtained. The measurements of Delta n as a function of applied electric field are important because of its potential application to quantum well based devices.