A combination underfill-dam and electrical-interconnect structure for an opto-electronic engine. The structure includes a first plurality of electrical-interconnect solder bodies. The first plurality of electrical-interconnect solder bodies includes a plurality of electrical interconnects. The first plurality of electrical-interconnect solder bodies, is disposed to inhibit intrusion of underfill material into an optical pathway of an opto-electronic component for the opto-electronic engine. A system and an opto-electronic engine that include the combination underfill-dam and electrical interconnect structure are also provided.