The exceptionally high efficiency and compactness of the diode laser have made it one of the key elements of the engineering systems throughout many different areas of industry. The decisive factor in the performance of the high-power diode laser in individual applications, is the quality of its beam emission. Applications in the high-power range require the use of micro-optical components, in order to maximise the use of light and, at the same time, to minimise the degree to which the beam quality depends on the direction of emission. These micro-optical components are vital to the basic function of the high-power diode laser and, more particularly, to its efficiency. In addition to the function-determining characteristics, the high levels of precision and reproducibility of the optics in serial manufacture along with the option of a monolithic structure will be of interest to laser manufacturers. The requirements arising from the basic construction of the diode laser, which must be met by micro-optics, will therefore be defined in the course of this contribution. In the second section, concepts for solutions, which take full account of these requirements, will be presented. Finally, optics used in high-power diode lasers will be discussed in the conclusion.