Tellurite glass optical fibres for lasers and amplifiers in the near infrared wavelength region

Tellurite glasses have been studied for several years as candidates for optical fiber lasers and amplifiers because they have a wide transmission region (0.35–5 um), good glass stability and corrosion resistance, a low vibrational energy (about 780 cm-1), low process temperature, and a high refractive index which increases the local field correction at the rare-earth ion site and leads to an enhancement of the radiative transition rates. The main results of this activity consisted in the design, fabrication and characterization of single mode low loss rare earth doped tellurite optical fibres doped with the Er3+ ions to obtain emission at 1.5 um and Ce3+ ions to increase the efficiency of the near infrared emission by minimizing visible up-conversion phenomena. The optical fibres were prepared by drawing glass preforms prepared by rod in tube and built in casting methods. The fibres were characterized in their attenuation loss by cut-back method and using mode profiling to demonstrate single mode operation.