Light coupling between stacked photonics chips

A method comprising:

• forming a first chip including a first waveguide core, a first ring resonator adjacent to a portion of the first waveguide core, a first dielectric layer over the first waveguide core and the first ring resonator, a first semiconductor substrate, and a first buried oxide layer;
• forming a second chip including a second waveguide core, a second dielectric layer over the second waveguide core, a second ring resonator in the second dielectric layer, a second semiconductor substrate, and a second buried oxide layer;
• and
• bonding a first surface of the first dielectric layer to a second surface of the second dielectric layer,
• wherein the first semiconductor substrate is separated from the first waveguide core and the first ring resonator by the first buried oxide layer, the second semiconductor substrate is separated from the second waveguide core and the second ring resonator by the second buried oxide layer, the second ring resonator is positioned adjacent to a portion of the second waveguide core, and the first ring resonator is positioned adjacent to the second ring resonator.