Vertical grating coupler

A vertical grating coupler, comprising:

• a first waveguide having a first grating formed therein, the first grating including a plurality of first grating ridges separated by a plurality first grating gaps;
• a second waveguide having a second grating formed therein, the second grating including a plurality of second grating ridges separated by a plurality second grating gaps;
• and
• a dielectric layer positioned between the first waveguide and the second waveguide, wherein the first grating, the second grating, and the dielectric layer are located in a vertical overlap region, each of the first grating and the second grating having a different grating period;
• wherein each of the plurality of first grating gaps and second grating gaps are filled with the dielectric layer;
• and
• wherein the first waveguide and the second waveguide each have a width of about 200 nanometers to about 2000 nanometers.

A method for using a vertical grating coupler, comprising:

• sending an optical input into a first waveguide, the optical input comprising a plurality of different wavelengths;
• transiting the optical input from the first waveguide through a first grating disposed on the first waveguide into a dielectric layer, wherein the dielectric layer has a thickness of about 1 nanometer to 1100 nanometers;
• transiting the optical input from the dielectric layer into a second waveguide through a second grating disposed on the second waveguide, the first grating and the second grating positioned opposite each other with the dielectric layer located therebetween;
• and
• sending the optical input through the second waveguide to an optical output.