Study On Broadband Near-infrared Luminescence Properties And Mechanism Of Bi Doped Glasses

With the rapid development of the internet and digital communication technology,super-high-capacity information transmission and super fast real-time information processinghave become the trend of the development of the optical fiber communication network.Therefore, broadband optical fiber amplifier with higher gain and broader gain bandwidth isneeded in the future. Due to the limitation of f-f transition of rare earth ion, the gainbandwidth of existing optical fiber communication systems which are based on EDFA isdifficult to exceed100nm, which may not meet the needs of the users in the near future.Raman fiber amplifiers can effectively overcome the shortcomings of rare earth ion dopedfiber amplifiers, but their structure is complex, and the amplifiers need high power pumpsources to achieve broadband amplification. These characteristics of Raman fiber amplifiershave limited their large-scale application, thus the exploration of new broadband optical fiberamplifier is very important.This paper introduced the recent development of optical amplifiers applied in the modernoptical communication system, and summarized the research progress of the gain mediumused in new broadband optical fiber amplifiers. Based on the above information, we chose thestudy on near-infrared （NIR） broadband luminescence properties and mechanism of Bi-dopedglasses as our research subject, and achieved broadband tunable NIR luminescence inBi-doped germanosilicate and borogermanate glasses. Besides, we came up with a modelexplaining NIR luminescence phenomena of Bi-doped glasses and fibers which waspreviously unknown and explored the preparation of Bi-doped mutil-component glass andfiber. The main research results and conclusions are as follows:1. In Bi-doped germanosilicate glasses, we found NIR luminescence is very sensitive tothe glass composition. The best composition with the strongest NIR luminescence is13Li₂O-23Al₂O₃-20GeO₂-43SiO₂-1Bi₂O₃（mol%）. In addition, Bi nanoparticles started toprecipitate, and the NIR luminescence decreased with increasing germanium oxide content. InBi-doped borogermanate glasses, we also found the NIR luminescence is very sensitive to theglass composition and the glass network structure influenced the NIR luminescence according to the IR spectra.2. The luminescence peak position in Bi-doped germanosilicate glasses andborogermanate glasses can be controlled by changing the excitation wavelength. Using thisfeature, we can achieve the tunable broadband NIR luminescence in Bi-doped glasses.Moreover, we found the intensity of the excitation wavelength dependent luminescence inBi-doped germanosilicate glass was weakened after heat treatment, and the excitationwavelength of the longest and shortest luminescence peak was inconsistent.3. From above experimental results, we proposed the NIR luminescence centers inBi-doped glasses and other materials are Bi⁰and Bi⁺ions, which contribute to the NIRemissions at long wavelength （¹250nm） and short wavelength （¹100nm）, respectively.4. We explored the low temperature preparation of transparent and homogeneousBi-doped multi-component glasses with good luminescence property, which provides thebasis for Bi-doped fiber preparation.