Heterobarrier blocking structure InGaAlP visible light laser diodes employing a thin active layer (0.04 &mgr;m) and asymmetry coatings have been fabricated. The high light‐output power operation with this heterobarrier blocking structure was investigated. The light‐output power versus cw current curve was linear up to 43 mW and a maximum light output power of 51 mW was obtained. A high‐power operation such as 20 mW was maintained at 40 °C. Stable oscillation in the fundamental transverse mode was obtained up to 30 mW. These results show that this heterobarrier blocking structure supplies a sufficient current confinement effect even under a high‐light output power operation.