Emission properties and structure of heavy metal oxide glasses

Emissions properties of glasses in the PbO-Ga2O3-Bi2O3 system doped with a variety of different rare-earth ions were reviewed with particular attention on the applications towards the amplification of the optical signals in the fiber-optic communication systems and for mid-infrared lasers. Due to the low vibrational phonon energy of the glasses, it was possible to realize the efficient emissions for the O-band and S-band amplification by doping Pr3+, Dy3+ or Tm3+. Amplification at these communication bands has not been possible when conventional oxide glasses were used as host materials. Network structure of the glass was made of n-fixture of GaO4 tetrahedra and PbO3/PbO4 polyhedra as a backbone. They are connected through bridging oxygens and a portion of these oxygen atoms are connected to three cations instead of two. Pb2+, ions also act as charge compensators as evidenced from the large amount of non-bridging oxygens in the glass network. Bi2O3 form BiO6 octahedra.