Abstract: A method is provided for producing a novel index-guided laser or laser array by MOCVD in a single growth step. A ridge or a number of ridges are first fabricated by dry or wet etching on a GaAs wafer; and n-and p-type epitaxial layers including cladding layers and an active layer are then grown on the entire wafer surface, forming the laser structure. One or more current blocking layers are incorporated into an upper cladding layer which is grown after the active layer. Due to migration-enhanced dopant incorporation and dopant diffusion during the growth, the current blocking layer is rendered ineffective in the vicinity of the ridges, thus forming a laterally restricted current path for carrier injection. The laser is index-guided on the ridges. This laser structure is extremely simple to produce since it requires no further photolithographic masking steps after growth, only metallization.