This paper analyzes the energy transfer process between the Er3+ and Tm3+ ions of Er-Tm co-doped tellurite fiber amplifiers pumped at 980 nm

sets up the rate and power propagation equations and obtains by simulation the law of variations of its amplification gain with the fiber length and pump power.The simulation results show that the amplifier can obtain a flat gain of as high as 50 dB at 1 440

1

540 nm by optimizing the fiber length and pump power.