Analysis of energy transfers between Tb3+ and Yb3+ codoped in borosilicate glasses

Energy transfer analyses are performed on Tb3+ and Yb3+ codoped in borosilicate glasses to assess their potential as gain media for green lasers and amplifiers under the 0.98 mu m band pumping. Based on experimental observations using the samples highly codoped with Tb3+ and Yb3+, a rate equation model of energy transfers between Tb3+ and Yb3+ is constructed considering the four types of energy transfers processes; (i) the cooperative energy transfer upconversion, (ii) the phonon-assisted energy transfer from Tb3+ to Yb3+, (iii) the cooperative cross relaxation, and (iv) the phonon-assisted energy transfer from Yb3+ to Tb3+. The rate equation model can simulate the experimental emission dynamics of Tb3+ and Yb3+ codoped samples well. It is clarified that a practical signal gain at 0.54 mu m can be obtained in Tb3+-Yb3+ codoped fiber under the 0.98 mu m band pumping. (c) 2009 Optical Society of America