High speed light modulator using multiple quantum well structures

Abstract

A semiconductor apparatus is provided. The apparatus has a multiple layer heterostructure having first and second material layers having first and second bandgaps, respectively and a semiconductor layer of a third bandgap being fabricated between said material layers, the bottom of the conduction band of said semiconductor layer is below the bottom of the conduction band of said material layers, and the top of the valence band of said semiconductor layer is above the top of the valence band of said material layers, the thickness of said semiconductor layer is chosen sufficient for carrier confinement effects within said semiconductor layer to influence the optical properties of said multiple layer heterostructure, and means for applying an electric field to the multiple layer heterostructure in order to vary an optical absorption coefficient and an index of refraction of the multiple layer heterostructure in response to the electric field. The apparatus is adapted for use as an optical absorption modulator or optical phase modulator, or as an electrically tuned Fabry-Perot cavity or as a polarization modulator, or as a nonlinear or bistable apparatus in which the operating point is varied by application of an electric field.