We put forward a new method for improving the output power stability of a cw laser. The basic idea is to replace the output mirror of a laser with a nonlinear mirror that is formed by a dispersive nonlinear Fabry–Perotétalon. Based on the semiclassical dynamic model for this system, first we derive the static conditions for this laser operating with stabilized output power, then we study the dynamic responses of output power to gain fluctuations. Both static and dynamic results show that, compared with normal lasers, the output power stability of our laser can be improved significantly when the output power fluctuations are caused by the fluctuations of the gain. The improvement of the output power can be explained by the fact that there exists an optical servoloop in this laser that is produced by the nonlinear mirror. © 1996 Optical Society of America.