A photonic device includes a PCB having an integrated circuit mounted thereon, with a cap mounted to the PCB and carrying a lens positioned over the integrated circuit. The cap is formed by: an outer wall mounted to the PCB, extending upwardly from the PCB, and surrounding a portion of the integrated circuit; a first retention structure extending inwardly from the outer wall and across the integrated circuit, the first retention structure having a hole defined therein; and a second retention structure having a hole defined therein, the second retention structure being affixed within the first retention structure such that the hole in the second retention structure is axially aligned with the hole in the first retention structure. The lens is mechanically constrained within the cap between the first retention structure and the second retention structure.