Hybrid-Pumped Few-Mode Erbium-Doped Fiber Amplifier for Gain Equalization

Pump selection plays an important role in an FM-EDFA when the active fiber is determined in an MDM system. In this letter, a hybrid-pumped FM-EDFA was proposed for low differential modal gain (DMG), combining both cladding pumping and forward LP ₀₁ core pumping. The cladding pumping was used to compensate for the absorption of the FM-EDF and core pumping was aimed at signal amplification adjustment. Not only the coupler damage caused by thermal energy conversion can be reduced, but also improve the utilization of pump power. When the power of core- and cladding pumping are set as 300 mW and 5 W, gains over 25.3 dB and a low DMG of 0.2 dB can be obtained experimentally between 3-LP modes.