Strong polarization-sensitive electroabsorption in GaAs/AlGaAs quantum well waveguides

We report the first measurements of perpendicular field electroabsorption (quantum confined Stark effect) in GaAs/AlGaAs quantum wells for light propagating parallel to the plane of the layers. This geometry is well suited for integrated optics. The absorption edge shifts to longer wavelengths with increasing field by as much as 40 meV, giving a modulation depth>10 dB. The strong dichroism present in this geometry is retained even at high fields, making polarization-sensitive electro-optical devices possible. We also demonstrate in the waveguide geometry optical bistability due to the self-electro-optic effect with 20:1 on/off ratio.