is introduced and dissertated in this paper. New research progress shows it has many attractive performances superior to that of conventional Er 3+ -doped fiber amplifier (EDFA)
semiconductor optical amplifier (SOA) and even fiber Raman amplifier (FRA)
such as full transparency to signal bit rate and modulation format
phase conjugation
very broad gain bandwidth
very low noise figure (NF) and excellent all-optical wavelength conversion function.