Abstract

In this paper we demonstrate a new concept for an electro-optical MSM-modulator structure based on the two-dimensional Franz-Keldysh effect.^1-3 In contrast to the spectra of bulk material, the absorption spectra of multiple-quantum-well structures exhibit excitonic resonances at each subband transition, even at room temperature. This is due to the exciton binding energy (typically 10 meV) in this quasi-two-dimensional system, being greater-than that of bulk material (typically - 4 meV for GaAs). If an electric field is applied perpendicular to the layers, the well-known quantum confined Stark effect^4,5 (QCSE) is observed. A variety of electro-optical modulator devices based on the QCSE have been successfully demonstrated during the last decade.^6,7

© 1995 Optical Society of America