Electro-optical modulators with folded gate layers

摘要

An optical modulator may include a lower waveguide, an upper waveguide, and a dielectric layer disposed therebetween. In one embodiment, the lower waveguide may include a u-shaped region within an optical mode of the light passing through the optical modulator. By conforming the dielectric layer to the surfaces of the u-shaped region, the amount of area of the dielectric layer within a charge modulation region is increased relative to forming the dielectric layer on a single plane. Folding the dielectric layer in this manner may improve modulation efficiency. In one embodiment, the u-shaped region is formed by using ridge structures that extend from an upper surface of the lower waveguide towards the upper waveguide. To aid in lateral confinement of the optical mode, the dielectric layer may be deposited on one side surface of the ridge structures while a different dielectric material is deposited on the opposite side surface.

主权项

1. An optical device comprising:
a first silicon waveguide comprising at least three ridge structures extending from an upper surface of the first silicon waveguide, the ridge structures defining at least two U-shaped regions on the upper surface; a dielectric layer disposed conformally on the upper surface in the two U-shaped regions; and a second silicon waveguide disposed conformally on a first surface of the dielectric layer opposite a second surface of the dielectric layer contacting the upper surface, wherein respective portions of the second silicon waveguide are disposed within the U-shaped regions, wherein the first silicon waveguide is doped a first conductivity type and the second silicon waveguide is doped a second, different conductivity type, wherein the second silicon waveguide includes a ridge portion extending away from an upper surface of the second silicon waveguide opposite a lower surface of the second silicon waveguide contacting the dielectric layer, wherein at least of one of the U-shaped regions and the ridge portion are disposed along an axis perpendicular to the upper surface of the first waveguide.