Abstract: In an opto-electronic head, an optic fiber is coupled with a laser or a light-emitting diode. According to the invention, a plane ceramic substrate acts as a reference plane for the alignment. It is separated into two zones: one zone dedicated to the semi-conductor device and one zone dedicated to the fiber. The second zone supports a heating resistor placed between two insulating layers. A heat barrier, consisting of a slit in the substrate, reduces heat transfers towards the layer to the minimum. To align the two components, a solder preform or polymer preform is put on the resistor. When the preform melts, it forms a drop in which the fiber 4 can be moved in three directions. The invention can be applied to opto-electronic systems.