Large optical‐cavity GaAs/GaAlAs double‐heterostructure stripe geometry laser with laterally effective step change of the refractive index is described. The stabilization of the transverse mode is achieved by regrowing an embedded stripe selectively on a large optical cavity, using metallo‐organic chemical vapor deposition. The near‐field and the far‐field patterns confirm the index guiding mechanism of the light. No kinks were observed in the light versus current characteristics up to light power of 200 mW/facet. The threshold current uniformity is comparable to those of gain‐guided lasers grown by metallo‐organic chemical vapor deposition.