Optical fibre amplifier having a gain flattening filter

A fiber optical network comprising at least a transmitting node and a receiving node and at least one optical fiber amplifier for amplifying light signals having wavelengths within a wavelength band, the at least one optical fiber amplifier comprising:

• an active optical fiber having an input end adapted to receive light signals to be amplified and an output end adapted to forward amplified light signals;
• a first pump source connected to inject pumping light of a first pump wavelength into the active optical fiber;
• a gain flattening filter connected between two lengths of the active optical fiber, between a first length at the input end of the active optical fiber and a second length at the output end of the active optical fiber;
• and
• a noise filter connected in the first length, between two portions of the first length, the noise filter being adapted to substantially block light waves having wavelengths at a gain peak of the pumped active optical fiber existing when there are no filters in the at least one optical fiber amplifier.