InGaAs/GaAs multiple-quantum-well modulators and switches

The design, fabrication and characterization of electrooptical modulators and switches based on pseudomorphic InGaAs/GaAs multipie-quantum-well (MQW) structures is presented. The absorption and refractive index changes (Delta alpha, Delta n) of Insub0.2Gasub0.8As/ GaAs MQW structures due to the quantum-confined Stark effect are examined in detail. The figures of merit Delta alpha/alpha 0 and Delta n/alpha 0 give information on the design of modulation and switching devices. Based on these results, we develop two types of efficient and high-speed modulators, vertical and waveguide modulators, and for the first time an InGaAs/GaAs intersectional X-type switch. Recent experimental results for each device are presented.