We present a phenomenological model that describes the self-starting proper
ties of a passively Q-switched fiber laser with a nonlinear mirror. The mod
el predicts a self-pulsing behavior above a critical value of the pumping p
arameter and is in good agreement with experimental data reported for an Yb
-doped fiber laser with a liquefying gallium mirror. (C) 2001 Optical Socie
ty of America.