An apparatus comprises a plurality of optical fibers and a lid member having one or more surfaces with grooves formed therein. The lid member defines a first plurality of grooves that are each dimensioned to partly receive an optical fiber of the plurality of optical fibers. The apparatus further comprises a substrate comprising a plurality of waveguides arranged at a predefined depth relative to a reference surface of the substrate, and a plurality of ribs extending from the reference surface. Each rib of the plurality of ribs is dimensioned to engage with a respective groove of a second plurality of grooves of the lid member. Engaging the plurality of ribs of the substrate with the second plurality of grooves of the lid member provides an optical alignment of the plurality of optical fibers with the plurality of waveguides.