All-fiber wavelength-widely tunable multi-pulse gain-switched Tm3+-doped double-clad fiber laser

We report a wavelength-widely tunable multi-pulse gain-switched Tm3+-doped fiber laser. The laser has a continuous wavelength-tunable range of 105 nm in 2 mu m band. The combination of Tm3+-doped double clad fiber and 793 nm pulsed pump source achieves large-energy pulse and multi-pulse operation. The single-pulse energy can reach 4.3 mu J and the multi-pulse energy can be 13.2 mu J. The effects of pump pulse energy, pulse repetition rate and pulse duration on multi-pulse generation are studied in detail. This easy-to-operate large energy 2 mu m pulsed fiber laser with adjustable pulse duration and repetition rate can provide a stable single-pulse or multi-pulse source in spectroscopy, medical surgery, material processing, etc.