We have fabricated a repetitively pulsating stripe geometry GaAlAs double‐heterostructure laser with a stripe by a shallow Zn‐diffusion inton‐GaAs top layer, generating high‐power fundamental transverse‐mode optical pulse trains. Spatially inhomogeneous current injection for exciting pulsations is achieved by a nonuniform breakover in space‐charge region under the Zn‐diffused stripe. These generated optical pulses have a peak power of more than 10 mW, a width of 0.4 ns, and a repetition frequency of 200 MHz–1 GHz.