The invention relates to an emission module for an optical signal transmission, comprising an emission unit which emits light of a certain wavelength, an emission unit substrate on which the emission unit is arranged or embodied, a detection unit which detects light of a certain wavelength, and a detection unit substrate on which the detection unit is arranged or embodied. According to the invention, the emission unit substrate and/or the detection unit substrate are transparent to the wavelength emitted by the emission unit, and the emission unit and the detection unit are superposed in the direction of the light emitted. The inventive solution enables the emission unit and the detection unit to be optically coupled without requiring additional optical components such as reflecting surfaces. Novel, compact optical system can thus be carried out in an emission module.