Abstract

The electric-field dependence of optical absorption has been studied extensively for bulk and multiple-quantum-well(MQW) semiconductors. In bulk semiconductors, it is known as the Franz-Keldysh effect. More recently, in MQW semiconductors, it is called the quantum confined Stark effect (QCSE)[1] and turns out to be much larger than in bulk semiconductors. Main consequences of the QCSE are broadening and red-shift of exciton absorption peaks. Direct modulation of optical absorption by the QCSE leads to an electro-optic modulator which has demonstrated fast optical modulation[2]. Major drawbacks of this absorption modulator are poor contrast and/or low absolute transmission. Moreover, since the wavelength of the light is usually close to an exciton peak, there is always strong absorption. This limits the maximum optical intensity to be handled by the modulator to a level below that of exciton saturation.

© 1988 Optical Society of America