The present invention provides a system, method and apparatus for improved electrical-to-optical transmitters (100) disposed within printed circuit boards (104). The heat sink (110, 200) is a thermal conductive material disposed within a cavity (102) of the printed circuit board (104) and is thermally coupled to a bottom surface (112) of the electrical-to-optical transmitter (100). A portion of the thermal conductive material extends approximately to an outer surface (120, 122 or 124) of a layer (114, 116 or 118) of the printed circuit board (104). The printed circuit board may comprise a planarized signal communications system or an optoelectronic signal communications system. In addition, the present invention provides a method for fabricating the heat sink wherein the electrical-to-optical transmitter disposed within a cavity of the printed circuit board is fabricated. New methods for flexible waveguides and micro-mirror couplers are also provided.