Patent ID: 8774569

Claim:
An electro-optic device comprising: an electro-optic substrate having a refractive index n s ; a first diffused waveguide within the electro-optic substrate for transmitting an optical signal through the device for electrically-induced modulation, the first diffused waveguide having a refractive index n w1 greater than n s ; first and second separate high confinement waveguides having refractive indices n c1 and n c2 , respectively, wherein n c1 and n c2 are greater than n w1 , wherein the first and second high confinement waveguides are optically coupled to each other, forming a directional coupler comprising a taper for adiabatic transfer of the optical signal, wherein the first high confinement waveguide is optically coupled to the first diffused waveguide, wherein the first high confinement waveguide and the first diffused waveguide form a first hybrid waveguide, wherein the first high confinement waveguide is at least partially disposed within the first diffused waveguide in the electro-optic substrate, the electro-optic device further comprising a second diffused waveguide having a refractive index n w2 greater than n s , wherein the second high confinement waveguide and the second diffused waveguide form a second hybrid waveguide, wherein the second high confinement waveguide is at least partially disposed within the second diffused waveguide in the electro-optic substrate, and the first and second high confinement waveguides are disposed in a horizontally separated side-by-side configuration, and wherein the first and second diffused optical waveguides of the first and second hybrid waveguides overlap in a coupling region.