10 kW peak power high pulse energy all-fiber based thulium-doped fiber laser at 2 μm

A stable pulsed thulium-doped fiber laser at 2 m is obtained based on gain-switched techniques, with the central wavelength of 1 979.4 nm. The pulse width and repetition rate of the seed laser can be tuned in the range of 60~200 ns and 1~100 kHz, respectively. After two-stage thulium-doped fiber amplifiers, the average output power of 2 m seed pulses is scaled up to 17.2 W at 20 kHz, and no obvious amplified spontaneous emission noise is observed. The measured output pulse width is 82 ns and the calculated maximum output pulse energy reaches as high as 0.86 mJ, which corresponds to a peak power exceeding 10 kW.