Enhancement in optical and microstructure properties of Er3+-doped phospho-tellurite glass thin film

Abstract Surface structure and photoluminescence lifetime of Er 3+ : 4 I 13/2 → 4 I 15/2 optical transition are two main factors determining the potential of glass thin films for integrated optical waveguide amplifiers. In this paper, the effects of different ambient gas atmospheres, i.e. pure O 2 and O 2 –He gas mixture, on the surface structure of the phospho-tellurite (PT) glass thin films which have been grown by the technique of pulsed laser deposition was studied. The surface analysis of the deposited thin films in the presence of the O 2 –He gas mixture showed a smoother surface and smaller particle size compared to the thin films deposited using a low background pressure of pure oxygen, which yields a reduction in the measure propagation loss from 0.78 to 0.41 dB/cm. It was found that the deposition of a thin layer of silica on top of the PT glass thin films increased the measured lifetime of the Er 3+ : 4 I 13/2 → 4 I 15/2 optical transition, as a result of the reduction in post deposition OH absorption by more than ∼500 cm −1 .