Abstract: An apparatus comprising a substrate comprising a base substrate, a conductive layer on the base substrate, and a solder resist layer on the conductive layer, a die including an optical area, the die being flip-chip bonded to the substrate, and an optical inter-connector optically coupled to the optical area and at least partially positioned between the die and the base substrate, the optical inter-connector positioned in a trench formed in the solder resist layer and the conductive layer. A process comprising providing a substrate comprising a base substrate, a conductive layer on the base substrate, and a solder resist layer on the conductive layer, forming a trench in the conductive layer and the solder resist layer, positioning a waveguide in the trench, and flip-chip bonding a die to the substrate, the die including an optical area, such that the optical area is optically coupled to the waveguide.