Electro-optical modulator with a vertical capacitor structure

An optical device, comprising:

• a right waveguide disposed on a dielectric substrate;
• a left waveguide disposed on the dielectric substrate, wherein the right and left waveguides are disposed on a same plane defined by the dielectric substrate, wherein the left waveguide is doped a first conductivity type and the right waveguide is doped a second, different conductivity type, and wherein the right and left waveguides have respective, opposing first and second sides;
• a vertical region separating the right and left waveguides, the vertical region extending vertically from the dielectric substrate to an upper surface of one of the right and left waveguides opposite a lower surface contacting the dielectric substrate, wherein the vertical region is filled with a dielectric material contacting the respective first sides of the left and right wavequides, wherein the left and right wavequides comprise respective raised wing portions that extend in a direction away from the dielectric substrate, the wing portions are located at the respective second sides of the left and right waveguides;
• and
• a dielectric ridge at least partially overlapping the vertical region, wherein a width of the dielectric ridge is equal to or greater than a width of the vertical region.