An EDFA hybrid gain control technique for extended input power and dynamic gain ranges with suppressed transients

A new approach for a hybrid gain control scheme based on an improved overlap of the all-optical and electrical feedforward gain control techniques for a single EDFA is presented. A wide input power operation range and a multi-level dynamic gain range are possible, enabling efficient gain control performance and allowing EDFA operation as pre, in line or booster amplifier. An EDFA characterization during add and drop of 1, 3, 7, 15, and 31 out of 32 input channels is also presented. The results show a maximum 0.6 dB deviation from the set EDFA gain value. By considering the EDFA response time, the interaction between optical and electrical controls shows a drastic reduction on EDFA transient impact to less than 2 ms with maximum overshoot/undershoot lower than 0.7 dB.