Electroabsorption in GaAs/AlGaAs coupled quantum well waveguides

A novel GaAs/AlGaAs coupled quantum well structure, consisting of two 46 Å wells separated by a 11.5 Å barrier, was embedded in a leaky waveguide. Polarization anisotropy and quantum-confined Stark effect absorption changes are observed, and a 14:1 modulator is demonstrated operating at the peak of the first light-hole transition. Although the lowest energy transitions behave as predicted by tunneling resonance calculations, higher energy states exhibit unusual behavior due to valence-band mixing.