Cladding-pumped nested-ring Tm fiber laser with 131 W single-mode output at 1907 nm (Conference Presentation)

Output power levels from 1907 nm Tm fiber laser sources are restricted by low lasing efficiency and challenging thermal management. Here we develop a novel fiber core structure where the Tm dopant material is confined to a ring within the larger undoped glass core. This evolution of dopant profiling has tripled the fiber device lengths and produced 131 W of 1907 nm emission with 64.5% absorbed slope efficiency. This, to the best of our knowledge, is the most efficient 1907 nm Tm fiber laser that has been demonstrated with the capability to perform beyond 100 W output power.