Improving the Power Efficiency in End-Pumped Gain-Guided Index-Antiguided Fiber Amplifiers

In this paper, we highlight the key reasons behind the poor power efficiency observed in multiple experiments in gain-guided index-antiguided (GG-IAG) fiber amplifiers and lasers. We show that by properly designing the fiber geometrical characteristics, it is possible to considerably improve the power efficiency of GG-IAG fiber amplifiers in end-pumping schemes.