Ultrafast thulium fiber laser system emitting more than 1 kW of average power.

Abstract

In this Letter, we report on the generation of 1060W average power from an ultrafast thulium-doped fiber chirped pulse amplification system. After compression, the pulse energy of 13.2μJ with a pulse duration of 265fs at an 80MHz pulse repetition rate results in a peak power of 50MW spectrally centered at 1960nm. Even though the average heat-load in the fiber core is as high as 98W/m, we confirm the diffraction-limited beam quality of the compressed output. Furthermore, the evolution of the relative intensity noise with increasing average output power has been measured to verify the absence of transversal mode instabilities. This system represents a new average power record for thulium-doped fiber lasers (1150W uncompressed) and ultrashort pulse fiber lasers with diffraction-limited beam quality, in general, even considering single-channel ytterbium-doped fiber amplifiers.