A study of light-hole electro-absorption in AlGaAs parabolic quantum wells, using a novel method

We report on polarization-resolved absorption measurements of parabolic qua ntum well structures embedded in an optical waveguide. This allows us to in vestigate in detail not only the heavy hole band structure, but also the li ght hole subbands whose contribution is suppressed in surface-normal incide nce experiments. We present a novel experimental technique utilizing a segm ented waveguide device that enables us to directly determine the modal abso rption caused by the parabolic quantum well interband transitions. Experime ntal results for electro-absorption are given and compared to theoretical p redictions. (C) 1999 Academic Press.