High-power single emitters and laser bars have established as widely-used light sources in many industrial applications such as materials processing or as pump source for solid state or fiber lasers.A steady increase in optical and cost efficiency is needed to lead the way into new markets.Following this intention, the epitaxial growth process as well as the design of the laser bars and single emitters is optimized to enhance the laser performance.Important parameters include the efficiency, the maximum output power,the wavelength stability and finally the reproducibility of the whole manufacturing process.To reach a high yield the epitaxial growth process is optimized with respect to maximal growth homogeneity on the wafer and from wafer to wafer.For high conversion efficiencies the design of the layer structure for single laser diodes emitting at 940nm is investigated by adjusting the number quantum wells.The laser diodes reach a wall-plug-efficiency of 62% at an optical output power of 12W.The electro-optic performance is enhanced for laser bars emitting between 880 nm and 1060 nm by improving the design of the waveguide and cladding layers.The Aluminum content in the cladding layers as well as the design of the waveguide layer especially near the QW leads to an improved performance at the wavelengths studied.Finally,we developed a wavelength stabilization for 976 nm laser devices applicable under production conditions which lead to very narrow and stable emission spectra of the laser diodes.