Bend-resistant fundamental mode operation in ytterbium-doped leakage channel fibers with effective areas up to 3160 microm(2).

We report fundamental mode operation in ytterbium-doped leakage channel fibers with effective areas up to 3160 microm(2). These fibers are bend-resistant. Lasers with slope efficiency ~60% and M(2) ~1.3 has been demonstrated. Bend loss and amplifier performance have also been characterized.