Abstract: Extending more usable optical bandwidth is an effective solution for dealing with the transmission capacity demand multiplication. It is with acceptable performance and easy for management by extending conventional CBand to super CBand. Adding Lband amplifier in parallel with CBand amplifier will bring some performance penalty, while almost double the bandwidth. The technical solution for further extending to super Lband is still under investigation, to study how to achieve high pump conversion efficiency as well as gain flatness.

Key words: erbium doped fiber amplifier, CBand, LBand, optical transmission system