Relaxation process of the 4I13/2 level of Er3+ in a borosilicate glass

Relaxation of 1.54 μm emission of the erbium doped borosilicate glasses with high rare earth solubility was investigated. When the erbium content is less than 0.2 wt%, multi-phonon relaxation is the predominant process of non-radiative relaxation. It is difficult to increase the quantum efficiency higher than 70% for erbium ions in this glass due to multi-phonon relaxation. Because of the good glass-formation ability and high rare earth solubility, this glass will be suitable as a host for rare earth ions with a large energy gap, such as Yb3+, Eu3+ or Tb3+.