What are main advantages and drawbacks of EDFAs?

The main advantages and drawbacks of EDFAs are as follows.

Advantages

• Commercially available in C band (1,530 to 1,565 nm) and L band (1,560 to 1,605) and up to  84-nm range at the laboratory stage.
• Excellent coupling: The amplifier medium is an SM fiber;
• Insensitivity to light polarization state;
• Low sensitivity to temperature;
• High gain: > 30 dB with gain flatness < ±0.8 dB and < ±0.5 dB in C and L band, respectively, in the scientific literature and in the manufacturer documentation
• Low noise figure: 4.5 to 6 dB
• No distortion at high bit rates;
• Simultaneous amplification of wavelength division multiplexed signals;
• Immunity to crosstalk among wavelength multiplexed channels (to a large extent)

Drawbacks

• Pump laser necessary;
• Difficult to integrate with other components;
• Need to use a gain equalizer for multistage amplification;
• Dropping channels can give rise to errors in surviving channels:dynamic control of amplifiers is  necessary.