RESONANT TUNNELING IN THIN-BARRIER MULTIPLE-QUANTUM-WELL ELECTROABSORPTION MODULATORS

We report the clear observation and characterization of room-temperature resonant tunneling in thin-barrier (35-angstrom) GaAs/AlGaAs multiple-quantum-well (MQW) structures (containing as many as 100 quantum wells) and discuss the effects on electroabsorption modulators. The characteristics of similar MQW devices with both thick (60-angstrom) and thin (35-angstrom) quantum-well barriers are studied and compared experimentally and found to be similar, except near the thin-barrier resonant-tunneling field. We present data suggesting a novel exploitation of resonant tunneling for high-power modulators by aligning the resonant-tunneling field with the appropriate wavelength for high absorption. Data from an asymmetric Fabry-Perot electroabsorption modulator are also presented. We also discuss the implications of resonant tunneling on optically bistable self-electro-optic effect devices.