Patent ID: 8548288

Claim:
A multi-chip module (MCM), comprising: a first substrate having a first surface, wherein the first substrate includes: a first optical waveguide disposed on the first surface; and a first optical coupler optically coupled to the first optical waveguide, wherein the first optical coupler is configured to couple an optical signal between a plane of the first optical waveguide and a direction out of the plane of the first optical waveguide; a second substrate having a second surface facing the first surface of the first substrate, wherein the second substrate includes: a second optical waveguide disposed on the second surface; and a second optical coupler optically coupled to the second optical waveguide, wherein the second optical coupler is configured to couple the optical signal between a plane of the second optical waveguide and a direction out of the plane of the second optical waveguide; and an optical interposer, positioned between the first surface and the second surface, configured to guide the optical signal between the first optical coupler and the second optical coupler, thereby reducing spatial expansion of the optical signal between the first optical coupler and the second optical coupler.