An all-optical gain controlled EDFA using a fast variable optical attenuator

The design and characterization of an all-optical gain controlled erbium doped fiber amplifier using an embedded variable optical attenuator in the feedback loop is presented. The gain (16-23 dB) is controlled by the attenuation level with high equalization (lower than 0.8 dB in all C band), low noise figure (around 5.3 dB), and absence of relaxation oscillations.