GaAs/AlAs quantum wells for electro-absorption modulators

Summary form only given. The authors demonstrate both theoretically and experimentally that the quantum-confined Stark effect leads to larger absorption changes in GaAs/AlAs quantum wells compared to the conventional GaAs/AlGaAs material due to the higher Γ confinement. The lower indirect valleys in the AlAs do not degrade the performance, and the exciton resonance is maintained at higher energy shifts. The improvement in exciton oscillator strength is 14% at zero bias and nearly 50% at 70-meV shift. The larger exciton strength at high fields has important applications for optical modulators and switches that operate at the long-wavelength side of the zero bias exciton