We demonstrated low‐noise and high‐power GaAlAs laser diodes with small astigmatism. The low‐noise characteristics are realized by self‐sustained pulsation due to the saturable absorption of a single‐quantum‐well located close to the triple‐quantum‐well active layer. The high‐power and small‐astigmatism characteristics are achieved by using a real refractive index guided self‐aligned structure. The lasers showed a relative intensity noise less than −130 dB/Hz under 10% optical feedback in a very wide output‐power range (5–35 mW), a stable fundamental transverse mode up to 150 mW, and astigmatism less than 1 &mgr;m. ©1996 American Institute of Physics.