Room-temperature operation of a GaAs/AlGaAs superlattice self-electrooptic-effect device

The authors report the room-temperature operation of a blue-shift SEED (self-electrooptic-effect device) using Wannier-Stark localization in a GaAs/Al/sub 0.3/Ga/sub 0.7/As superlattice. They demonstrate that large modulation can be obtained over a wide spectral range and bias with contrast comparable to MQW (multiple quantum-well) SEEDs. Wannier-Stark localization associated with a blue shift of the superlattice (SL) absorption edge was clearly observed in the photocurrent measurements. Bistability of the SL SEED was obtained over a wide spectral range and was almost constant between 745 and 755 nm. The demonstration of large modulation bandwidth and optical switching behavior of the SL SEED makes this device an excellent candidate for optical signal processing and optical computing.