Electroabsorption optical modulator

Apparatus comprising:

• a semiconductor optical waveguide;
• a bilayer consisting of a transparent conductor layer and a gate dielectric layer next to the transparent conductor layer, wherein the bilayer overlies and directly contacts the semiconductor optical waveguide;
• a metal contact layer that overlies the bilayer;
• a first electrical contact electrically connected to the metal contact layer;
• and
• a second electrical contact electrically connected to a conductive layer that underlies the gate dielectric layer such that a voltage applied between the first contact and the second contact produces an electric field across the gate dielectric layer;
• wherein:
• the transparent conductor layer is optically coupled to the semiconductor optical waveguide and electrically coupled to the first or the second electrical contact;
• the transparent conductor layer comprises a transparent conducting oxide material;
• and
• the metal contact layer comprises titanium nitride or a metal or combination of metals selected from the group aluminum, copper, silver, gold;
• and wherein the layer of transparent conductor comprises cadmium oxide and the gate dielectric layer comprises magnesium oxide forming an interface with the cadmium oxide.