Low-noise performance of gain-clamped erbium-doped fiber amplifiers by loop lasing oscillation

The noise characteristics of gain-clamped EDFA by using a feedback loop was investigated theoretically and experimentally. It is proposed for the first time that the gain-clamped EDFA can be operated with considerable low noise figure if the operation point, i.e., the degree of the feedback and the laser loop structure was selected properly.