Aninsitudry etching and metalorganic chemical‐vapor deposition regrowth process is developed to realize AlGaAs/GaAs buried heterostructure with an arbitrary shape and orientation, and is applied to edge‐emitting laser diodes with a complex cavity structure and surface‐emitting laser diodes (SELD). At present, threshold currents for both edge‐emitting and surface‐emitting lasers are similar to that of a conventional ridge‐stripe waveguide laser or proton‐isolated SELD, indicating that there is considerable surface recombination at regrown interfaces. Surface recombination velocity at the regrown interfaces is estimated from the size effect of lasing characteristics.