Low Voltage Phase Modulation in GaAs/AlGaAs Quantum Well Optical Waveguides.

We report GaAs/AlGaAs quantum well waveguide phase modulators with high phase shift coefficients, as large as 520 degrees per Volt-mm. By operating at wavelengths far below the bandedge and applying DC bias we achieve large electrooptic modulation with low absorption loss in device lengths on the order of 100microns and drive voltages on the order of 5 Volt.