Recent Progress on Submarine Optical Amplifiers

Submarine networks look like a teenager if compared to terrestrial ones. Although this teenager passed a difficult adolescence, he seems to have a brilliant future. As bandwidth demands increase, both optical technology and Space Division Multiplexing (SDM) promise to cover future needs and overcome problems and difficulties of the demanding submarine environment. One of the most critical sectors in submarine networking is amplification. In this work we survey on all recent progress of submarine amplifier technologies. Based on recently reported milestones and research, we also try to predict the amplification future of this young and promising teenager.