Yb-free Er-doped 980 nm pumped single-frequency fiber amplifier with output power of 54W and near-diffraction limited beam quality

摘要

The recent significant increase in output power of high brightness pump diodes has led to interest in high power cladding pumped Yb-free Er-doped fiber laser systems. Here, resonant pumping between 1480 and 1530 nm [1] is attractive due to the low quantum defect, but has the drawback of limited pump power from - especially commercially available - high brightness pump diodes. Therefore, we decided to investigate the power scaling of Yb-free Er-doped single frequency amplifiers to output power levels of multiple 10W with non-resonant pumping around 980 nm. To the best of our knowledge, the achieved power levels are several times higher than reached with previous Yb-free Er-doped amplifier systems with comparable near-diffraction limited beam quality [1,2].