Franz–Keldysh electrorefraction and electroabsorption in bulk InP and GaAs

Abstract
Franz–Keldysh electrorefraction and electroabsorption were measured for semi-insulating InP and GaAs at several electric fields and several wavelengths near the absorption edge. For InP, the experimental results are described well by an effective mass approximation theory with a correction that accounts for the exponential absorption tail. It is shown that, at least in InP, Franz–Keldysh electrorefraction is under some conditions much stronger than the Pockels effect.