This work explains a method for optoelectronic integration of an heterojunction bipolar transistor (HBT) and a waveguide electroabsorption modulator (EAM). For this the epitactical layers of the individual devices based on III/V-semiconductors are merged into each other. The method has the advantage to reuse layers and results in a layer stack, which is easier to process technologically. Additionally to the manufacturing of the individual devices HBT and EAM, this integration enables a multifunctional device, which works in the optical and electronic regime simultaneously (HBT-EAM). This corresponds to an EAM with integrated amplifier. Presented are epitaxy, technological processing and measurement results.