Saturation effect of EDFA on frequency filtering characteristics of active fiber ring resonators

摘要

The saturation effect of EDFA on frequency filtering characteristics of active fiber ring resonators is studied theoretically and experimentally in this paper. When input signal power is large enough, it would enter the saturation regime and lower EDFA gain, thus, the finesse of active fiber ring resonator descends as the same when lower pump power is injected, all of which are confirmed by comparing the output signal spectrums with different input signal power and different pump power in our experiments. By using the atom rate equations of EDFA and the multi-light interference theory, the experiment results are well explained. On considering this EDFA saturation effect, the optimization of active fiber ring resonator filter is also discussed. To obtain both narrower linewidth light and larger output power, one should use input coupler with small coupling ratio and output coupler with large coupling ratio to construct an active fiber ring resonator filter, making sure that saturation effect of EDFA can not occur.