Erbium-ytterbium co-doped hollow optical fibre laser

An erbium-ytterbium co-doped hollow optical fibre (HOF) laser generating up to 2.5W of output power in the 1550nm spectral region with a power conversion efficiency of 26% with respect to the launched pump power is demonstrated. A significant reduction of ytterbium co-lasing at 1060nm is observed with increasing core thickness in the HOF, which is believed to be correlated with the signal overlap factor at 1550nm that increases as the core thickness increased.