EXCITONIC BAND-EDGE ELECTRO-ABSORPTION IN MULTIPLE-QUANTUM-WELL WAVEGUIDE MODULATOR STRUCTURES

Abstract

Electric field induced changes in the excitonic band-edge absorption spectra of Multiple-Quantum-Well (MQW) structures were investigated theoretically and experimentally. A comparison was made of three different exactly solvable methods for calculating quantum-well energies. The small effects due to conduction-band nonparabolicity and valence-band mixing were included. Transmission spectra were recorded for an In.12Ga.88As-GaAs optical waveguide modulator structure. The theoretical model was used to predict the changes in the long-wavelength tail of the band-edge absorption for different electric fields.