Theoretical analysis of gain characteristics of Er/sup 3+/-Tm/sup 3+/-codoped tellurite fiber amplifier

The rate and power propagation equations of Er³⁺ and Tm ³⁺-codoped tellurite fiber amplifier pumped by 800-nm laser are presented and solved to analyze the dependences of gain at both 1470 and 1530 nm on the codoping concentration of Er³⁺ and Tm³⁺, fiber length, and input signal power. The numerical results show that with pump power of 200 mW and fiber length of 1.5 m, the gain at both 1470 and 1530 nm may reach 12.0 dB when the codoping concentration of Er³⁺ and Tm³⁺ reach 4.0times10 ²⁵ ions/m³, 3.2times10²⁵ ions/m³ , respectively. The fiber length and codopant concentrations are proposed to make the two channels equivalently amplified