Self‐oscillations of V‐channeled substrate inner stripe (VSIS) lasers with index guiding and the influence of external feedback on low‐frequency noise generation are presented. The self‐oscillation is induced by means of shortening a cavity length of VSIS laser to 110 &mgr;m. VSIS lasers with self‐oscillation have the fundamental linewidth of 0.56 A˚ below 3 mW and are not sensitive to both phase and amplitude of the externally reflected light. Signal to noise ratio of short‐cavity VSIS laser at 1 MHz with a 10‐KHz bandwidth was 97 dB at 0.05% optical feedback.