A cap assembly for optical communications comprising a housing that includes a front side perpendicular from a bottom side, opposing parallel first and second sides perpendicular from the bottom side, and a back side disposed perpendicularly between the first side and the second side offset from respective ends of the first side and the second side opposite the front side. The back side includes an opening there-through and a three-sided ledge formed along an interior of the first side leg, an exterior of the back side, and an interior of the second side leg. The cap assembly further includes a window configured to contact the three-sided ledge of the back side, the glass panel covering the opening there-through and attached to the assembly via a solder pre-form.