A new type of GaAs-GaAlAs stripe-geometry laser with an appreciably simplified fabrication process is described. Owing to the excellent lateral current confinement of this structure, low threshold current densities are achieved even for very narrow stripe widths. In addition, the built-in passive wave-guiding stabilises the fundamental horizontal transverse mode, thereby avoiding nonlinearities in the light output against current characteristic. For 3μm wide and 175 μm long lasers, threshold currents of 30–35 mA are achieved and stable transverse and longitudinal monomode emission has been observed up to more than 5 mW light power output.