High power 100fs fiber oscillator

Recent advances concerning the performance of mode-locked fiber lasers have been made, working at all normal cavity dispersion whilst exploiting strong dissipation for pulse shaping. The current limitation of mode locked step-index single-mode fiber lasers arises mainly from high nonlinearity accumulated in the small fiber core. By scaling the mode area exceptional performances in terms of pulse energy and peak power have been demonstrated using large-mode-area (LMA) photonic crystal fibers. In this contribution a ring cavity, which is mode-locked by non-linear polarization rotation (NPR), features a very large mode area ytterbium-doped large-pitch photonic-crystal fiber. The combination of strongly decreased nonlinearity with a non-absorptive instantaneous mode-locking mechanism enables the generation of multi megawatt peak power pulses. This comes along with an average power, which is more than twice as high as achieved with previously reported mode-locked fiber lasers.