Silicon-based electro-optic device

A silicon-based electro-optic device comprising:

• a silicon body region doped to exhibit a first conductivity type;
• a silicon gate region doped to exhibit a second conductivity type, the silicon gate region being disposed at least in part over the silicon body region to define a contiguous area between the silicon body region and the silicon gate region;
• a dielectric layer disposed in the contiguous area between the silicon body region and the silicon gate region, the combination of the silicon body region and the silicon gate region with the interposed dielectric layer defining an active region of the electro-optic devices;
• a first electrical contact coupled to the silicon gate region;
• and
• a second electrical contact coupled to the silicon body region,
• wherein upon application of an electrical signal to the first electrical contact and the second electrical contact, free carriers accumulate, deplete or invert within the silicon body region and the silicon gate region on both sides of the dielectric layer at the same time, such that an optical electric field of the optical signal substantially overlaps with a modulation area of free carrier concentration in the active region of the electro-optic device,
• a rib waveguide is formed by means of the silicon body region, the silicon gate region and the dielectric layer,
• a first electrical contact is coupled to a slab part of the rib waveguide,
• the rib part has a region coupled to an electrode contact region where thickness of the electrode contact region of rib part is thicker than around rib part, and
• a position of the electrode contact region of the rib part is located at a position of center of the waveguide where an effective index value of the rib waveguide in a zeroth-order mode is constant when the distance between rib waveguide and the electrode contact region varies.