Electric field induced quantum well waveguides

Abstract

The invention is directed to laterally confined optical waveguide devices in semiconductors using quantum-well structures. An optical waveguide having a core comprising at least one quantum-well structure is interposed between first and second cladding regions such that an optical beam inserted into the core region spreads laterally with respect to a primary direction of the beam. Contacts are fabricated on the surface of the top cladding region and serve as means for applying an electric field to the core of the waveguide. The electric field induces a change in the refractive index of the portion of the quantum-well structure within the field. The change in the refractive index functions to laterally confine the propagation of the optical beam to the region of the core within the electric field, while maintaining a low loss transmission. Controlling the lateral propagation of an optical beam by way of an applied electric field allows a family of low-loss optical devices such as modulators and switches to be realized. Such devices can be fabricated without regard to their orientation in the crystalline structure of the semiconductor material.