An optoelectric subassembly including a receptacle assembly with an optoelectric device mounted therein to define a light axis. The receptacle assembly includes an optical fiber mounting structure defining an opening with an end of an optical fiber received therein. The mounting structure and opening are designed to position the received optical fiber with an end facet substantially perpendicular to the light axis. A first lens is mounted in the receptacle assembly adjacent the optoelectronic device in the light axis and a ball lens is mounted in the receptacle assembly and positioned in the light axis. The ball lens is mounted so as to be in abutting engagement with the facet of an optical fiber inserted into the opening. By forming the ball lens with a diameter equal to the diameter of a mounting ferrule on the end of the fiber and also equal to the diameter of the ferrule receiving opening, the ball lens is self-aligning.