Cladding-pumped high-power mode-locked thulium laser based on fiber prepared by powder sinter technology

Recently, a considerable progress has been done on power and energy scaling of pulsed thulium doped fiber amplifiers working at l ~ 2 mm. However, obtaining a high average power directly at the oscillator output remains a real challenge mainly due to the anomalous waveguide dispersion at this wavelength range. Usually energy scaling of mode-locked oscillators is based on dissipative solitonic (DS) regime which requires normal net cavity dispersion. For l > 1.5 mm, one must use dispersion compensating elements inside the cavity to provide such an operating regime. Typically, pulse energy measured directly at the output of a passively mode-locked thulium fiber oscillator in net normal dispersion cavities is in order of few mW. In our contribution, we propose to use a cladding-pumped Tm-doped fiber combined with a net normal dispersion cavity enabling the generation of high average power, high energy picosecond pulses (185 mW, 21 nJ, 16 ps). The step-index double-clad Tm-doped fiber has been fabricated using one of the newest glass manufacturing technologies which has already demonstrated very good capabilities for the fabrication of efficient and homogeneous active material.