Embodiments herein relate to systems, apparatuses, techniques for an optical waveguide that includes a plurality of pillar structures that are in an optical path between the optical waveguide and a PIC. In embodiments, the plurality of pillar structures form an evanescent coupling structure that increases the alignment tolerance between the PIC and the optical waveguide. In embodiments, an end of each of the plurality of pillar structures may include a mass of material, such as gold, silver, or copper, that light from the PIC interacts with in a Plasmon effect to focus the light on to the optical waveguide. Other embodiments may be described and/or claimed.