New Concept of Multilayer Photorefractive Device

We propose a multilayer photorefractive device based on the association of two classes of materials respectively designed for transport and electro-optic properties. This device consists in repeated elementary cells, each of them made with an electro-optic material layer embedded between two different photoconductive layers. In these layers (respectively hole and electron dominated) deep levels allow to build-in a space charge field distribution under periodic illumination, giving rise in the electro-optic layer to a perpendicular electric field component, yielding to a diffraction grating. Its efficiency can be increased by the repetition of these cells. InGaAsP/InP MQW can be used as electro-optic material and semi-insulating InP:Ti and InP:Fe as respectively electrons and holes dominated photoconductors. We present simulation results of the behaviour of this device under electric bias and of the coupling effects between adjacent layers which yield space charge field modulation well over the usual diffusion limit.