A comparative study of the spectroscopic properties at 1.5 um of erbium-activated fluoride and tellurite glasses

A comparative study of the spectroscopic properties at 1.5 mum of erbium-doped fluoride and tellurite glasses has been performed. Emission in the third telecommunications window has been observed upon excitation at 514.5 nm and the lifetime of the I-4(13/2) level has been measured. Infrared-to-visible upconversion emission upon continuous-wave laser excitation at 976 nm has been detected in the different hosts. The upconversion results in green and red emissions, whose intensity has a quadratic dependence on the excitation power. Lifetime measurements have been performed in order to clarify the contributions of excited-state absorption and energy transfer to the upconversion process.