We report on the development of high-power laser diodes and laser bars emitting in the visible red spectral region. In contrast to the normally used epitaxial structure consisting of AI(Ga)InP waveguide and cladding layers embedding an GaInP quantum well (QW) we also investigated AlGaAs as material for the cladding layers in a symmetric and in an asymmetric design. The laser performance of the different structures is compared. AlGaAs as p-cladding layer enables the use of carbon instead of zinc as p-dopand resulting in a reduced diffusion tendency of the doping material and a higher possible doping level. Furthermore, the influence of QW number and thickness on the laser performance is investigated. With optimized layer structures 5-mm wide laser bars at 650 nm with a maximal output power of 55 W in pulsed operation were realized. (c) 2006 Elsevier B.V. All rights reserved.