Near-Infrared Emission and Energy Transfer Mechanism of Er3+ /Nd3+ /Tm3+ Co-Doped Tellurite Glasses

In order to meet the increasing demand for the transmission capacity of Dense Wavelength Division Multiplexing (DWDM) systems due to the rapid development of communication networks, the performance requirements for the core device of the DWDM system, Erbium Doped Fiber Application Amplifier (EDFA), are also getting higher and higher. Tellurite glass has become an ideal material to replace the traditional erbium-doped silica fiber because of its high solubility of rare earth ions, low phonon energy and high refractive index. Rare earth-doped tellurite glass can be used as the ideal gain medium of broadband fiber amplifiers to achieve effective signal amplification. Therefore, improving the spectral performance of erbium-doped tellurite glass and expanding its amplification bandwidth are of great significance for the expansion of the DWDM system. In this paper, Er3+, Nd3+ and Tm3+ are co-doped to improve the amplification bandwidth of tellurite glasses to obtain ultra wideband luminescence. Er3+, Nd3+, and Tm3+ ions can generate luminescence in 1.55, 1.34 and 1.85 mu m bands through the transition, and these three near-infrared emission bands are adjacent to each other. The luminescence of tellurite glass in a continuous spectrum is realized through energy transfer (ET) between ions by means of co-doping of three ions. In TeO2-WO3-ZnO-Na2O-Er2O3 tellurite glass, Er3+ /Nd3+ ions were doped first, and the energy transfer mechanism between Er3+ /Nd3+ ions was analyzed. It was found that the glass had a better luminous intensity when the concentration of Er2O3 and Nd2O3 was 1 and 0.1 mol%, respectively. On this basis, Er3+ /Nd3+ /Tm3+ doped tellurite glasses with good thermal stability were prepared by high-temperature melting annealing. Energy transfer occurs between Er3+, Nd3+ and Tm3+ ions, and three luminescence bands with luminescence centers of 1.3, 1.5 and 1.8 mu m are generated in the range of 1 250 similar to 2 100 nm, covering the whole O, E, S, C, L and U bands. The Full Width at Half Maxima (FWHM) increases to 131.68 nm at 1.5 mu m, and the FWHM reaches 251.75 nm at 1.8 mu m. The mechanism of energy transfer between rare earth ions during doping of three kinds of rare earth is analyzed in detail. The spectral results show that Er3+ /Nd3+ /Tm3+ triple tellurite glass is an effective material for the design of ultra-wideband fiber amplifiers when the doping concentrations of Er2O3, Nd2O3 and Tm2O3 are 1, 0.1 and 0.2 mol%, respectively.