Spectroscopic Properties Study Of The Tellurite Glasses

In recent years, the demand for increasing transmission capacity and extending system is urgent and the broad band fiber is applied in more and more fields, with the rapid development of computer networks and other data-transmiting services. The significant symbol for this trend is the appearance of the new technology for combining the dense wavelength division multiplexing (DWDM) system and broadband amplifier now. However, C-band (1530-1565nm) magnified, the Er³⁺-doped SiO₂-based fiber amplifier (EDFA) ,can not satisfy the high-speed and large-capacity transmission any more, it is urgent to get new glass host used for the fiber amplifier which has the qualities of broadening and flattening the gain spectra. More and more other new rare-earth material doped based glass fiber has been discovered in recent years, especially, the application foreground of Er³⁺-doped tellurite glass fiber is vast in super broadband communications. The objective of this work is to develop a new kind of glass, which may be used as host material for broadband erbium-doped fiber amplifiers and erbium-doped optical waveguide amplifiers. Based on the investigation of the structure of tellurite glasses and the spectroscopic properties of erbium-doped tellurite glasses, the potential application for the glasses used as host material for broadband optical amplifiers can be evaluated. The exordium briefly introduced the principles and researching development in the tellurite fiber amplifier, and studied the special merits of tellurite optical fiber as gain medium in fiber amplifier, comparing to conventional SiO2-based optical fiber and other based fiber. It also summarized the developing status of the glass composition, thermal stabilities, chemical stabilities and spectroscopic properties in our country and abroad. The conclusion is that the tellurite glass can be used as an ideal glass host for broadband fiber amplifier. An introduction of the experimental materials, instrument and operating processes was given. And it especially explained the methods and principle of testing the spectroscopic properties in detail in the part of experimentation. In Chapter Three, the structure of tellurite glasses were introduced and analyzed. Raman spectra and Infrared spectra were measured and compared, at the same time, Raman spectra temperature effect of tellurite glasses were studied. In the Fourth Chapter, the spectroscopic properties of tellurite glasses were discussed, which was an important content in this article. Absorption spectrum and fluorescent spectrum were measured to determine stimulated emission cross sections of Er³⁺ in tellurite glasses.Fluorescent lifetimes were measured and would decrease when Er³⁺ ion concentration increases.The conclusion also indicated that tellurite glass was a more ideal glass host for broadband fiber amplifier compared to other glasses. Addi- tionally, the up-conversion phenomenon was studied about the tellurite glass and the mechanism and the difference of up conversion were construed in Er³⁺-doped tellurite glasses. The up-conversion phenomenon was very harmful to fiber amplifier and some measures should be taken to avoid it. Finally, all results of present work are outlined, and it is suggested that something should be done in the next stage.