GaAs/AlGaAs multiple-quantum-well in-line fiber intensity modulator

Abstract
We demonstrate a GaAs/AlGaAs multiple-quantum-well in-line fiber optic intensity modulator. Based on evanescent wave coupling between a GaAs/AlGaAs multiple-quantum-well waveguide and a single-mode fiber, this device concept combines the inherent advantages of in-line fiber devices with high-speed GaAs integrated optoelectronics. The GaAs waveguide uses distributed Bragg mirror layers to phase match to the low-index fiber. Intensity modulation of the transmitted light through the fiber is achieved by tuning the effective propagation index of the GaAs waveguide via the quantum-confined Stark effect. Initial structures show a modulation contrast (ΔT/T) of more than 53%, with an applied voltage of 5 V.