Effects of ion-clusters on the intensity noise of heavily erbium-doped fiber lasers

Using a modified ion-cluster model, we study the intensity noise of heavily erbium-doped fiber lasers in which some large ion-clusters may exist. Theoretical results show that the low-frequency noise is enhanced greatly when many erbium ions are in clusters. The fiber laser system is very sensitive to perturbations in the pump rate, and imposes a high demand on the stability of the pump source.