Systems and methods may couple on-chip optical circuits to external fibers. An SOI waveguide structure may include mirror structures and tapered waveguides to optically couple optical circuits to fibers in a vertically oriented external connector. The mirror structure(s) may be angularly disposed at the ends of the silicon waveguide structure. An oxide layer may cover a buried oxide layer and the silicon waveguide structure. The tapered waveguide(s) may have a narrow end and a wide end. The narrow end of the tapered waveguide(s) may be disposed above the mirror structures. The tapered waveguide(s) may extend through the oxide layer from the narrow end in a direction perpendicular to the silicon waveguide structure. An external connector may fit over the tapered waveguide(s) and uses a fiber array traveling through a connector body to optically couple to the external fiber.