Compact and efficient integrated photonic device for coupling light on- and off-chip

A system comprising:

• an on- and off-chip optical coupler comprising:
• a first optical prong wherein the first optical prong is airclad;
• a second optical prong wherein the second optical prong is airclad, the second optical prong being symmetrical to the first optical prong;
• a suspended optical waveguide with which the first optical prong and the second optical prong merge, and a bottom surface of the suspended optical waveguide disposed above a trench at least along a width of the suspended optical waveguide;
• wherein:
• a distance from an axially outer tip edge of the first optical prong to an axially outer tip edge of the second optical prong is greater than a planar width of the optical waveguide;
• the first optical prong and the second optical prong are each tapered from the optical waveguide;
• and
• the first optical prong and the second optical prong together provide on- and off-chip coupling through the optical waveguide.