Out-of-band electronic gain clamping for a variable gain and output power EDFA with low dynamic gain tilt

In conclusion, the Er-doped fibre amplifier (EDFA) configuration presented allows variable gain or output power with minimal dynamic gain tilt. The use of an out-of-band probe laser and electronic feedback makes efficient use of the pump power while allowing fine control and adjustment of the EDFA gain but without sacrificing any of the EDFA transmission bandwidth.