A multiple piecepart alignment configuration for mating at least one optical fiber with a silicon photonic subassembly including a plurality of optical waveguides, the multiple piecepart alignment configuration comprising: a box-shaped fiber holder component including: a plurality of grooves formed along an inner surface of a bottom portion of the box-shaped fiber holder, each groove for supporting a separate optical fiber of the at least one optical fiber upon insertion into a side opening of the box-shaped fiber holder; a grooved lid component including: a plurality of mechanical registration features (22, 24) formed in a first region of the underside of said grooved lid; and a plurality of grooves formed in a second region of the underside of said grooved lid, the plurality of grooves for sliding over and encasing the at least one optical fiber disposed within the box-shaped fiber holder; and a silicon photonic subassembly including: a plurality of optical waveguides formed therein; a plurality of alignment detents (32, 34) corresponding in size and location with the plurality of mechanical registration features (22, 24) formed on the underside of the grooved lid such that upon placing the grooved lid onto the silicon photonic subassembly, the plurality of mechanical registration features (22, 24) enter the plurality of alignment detents (32, 34), providing alignment and mechanical attachment therebetween; and a plurality of channels formed along an endface thereof adjacent to the box-shaped fiber holder, the plurality of channels for supporting endface terminations of the at least one optical fiber in alignment with the plurality of optical waveguides formed within the silicon photonic subassembly. a box-shaped fiber holder component including: a plurality of grooves formed along an inner surface of a bottom portion of the box-shaped fiber holder, each groove for supporting a separate optical fiber of the at least one optical fiber upon insertion into a side opening of the box-shaped fiber holder; a grooved lid component including: a plurality of mechanical registration features (22, 24) formed in a first region of the underside of said grooved lid; and a plurality of grooves formed in a second region of the underside of said grooved lid, the plurality of grooves for sliding over and encasing the at least one optical fiber disposed within the box-shaped fiber holder; and a plurality of mechanical registration features (22, 24) formed in a first region of the underside of said grooved lid; and a plurality of grooves formed in a second region of the underside of said grooved lid, the plurality of grooves for sliding over and encasing the at least one optical fiber disposed within the box-shaped fiber holder; and a silicon photonic subassembly including: a plurality of optical waveguides formed therein; a plurality of alignment detents (32, 34) corresponding in size and location with the plurality of mechanical registration features (22, 24) formed on the underside of the grooved lid such that upon placing the grooved lid onto the silicon photonic subassembly, the plurality of mechanical registration features (22, 24) enter the plurality of alignment detents (32, 34), providing alignment and mechanical attachment therebetween; and a plurality of channels formed along an endface thereof adjacent to the box-shaped fiber holder, the plurality of channels for supporting endface terminations of the at least one optical fiber in alignment with the plurality of optical waveguides formed within the silicon photonic subassembly. a plurality of optical waveguides formed therein; a plurality of alignment detents (32, 34) corresponding in size and location with the plurality of mechanical registration features (22, 24) formed on the underside of the grooved lid such that upon placing the grooved lid onto the silicon photonic subassembly, the plurality of mechanical registration features (22, 24) enter the plurality of alignment detents (32, 34), providing alignment and mechanical attachment therebetween; and a plurality of channels formed along an endface thereof adjacent to the box-shaped fiber holder, the plurality of channels for supporting endface terminations of the at least one optical fiber in alignment with the plurality of optical waveguides formed within the silicon photonic subassembly.