Energy scaling of femtosecond and picosecond fiber oscillators beyond the microjoule level

摘要

We report on the generation of microjoule level picosecond pulses from a mode-locked Yb-doped LMA fiber laser operating in the purely normal dispersion regime. The self-starting oscillator stabilized with slow relaxation semiconductor saturable absorber (SAM) emits 11 W of average power at a pulse repetition rate of 10 MHz, corresponding to a pulse energy of 1.1 μJ. The laser produces a 0.4 nm narrow emission line with 310 ps output pulses. In the femtosecond operation, the oscillator stabilized with fast relaxation SAM emits 9 W of average power at a pulse repetition rate of 9.7 MHz, corresponding to a pulse energy of 927 nJ. The laser produces positively chirped output pulses of 8 ps which are compressed down to 711 fs, corresponding to megawatt peak power. To our knowledge this is the first time that mode-locked fiber oscillators can generate higher pulse energies of beyond microjoule-level at high average output power.