Scaling the effective area of higher-order-mode erbium-doped fiber amplifiers

We demonstrate scaling of the effective area of higher-order mode, Er-doped fiber amplifiers. Two Er-doped higher-order mode fibers, one with 3800 mu m(2) A(eff) in the LP0,11 mode, and one with 6000 mu m(2) effective area in the LP0,14 mode, are demonstrated. Output beam profiles show clean higher order modes, and S-2 imaging measurements show low extraneous higher order mode content. CW and pulsed amplifier experiments are reported. Nanosecond pulses are amplified to 0.5 mJ pulse energy with 0.5 MW peak power. (C) 2012 Optical Society of America