Kerr-lens mode-locked GHz-repetition-rate Yb:CYA laser with 11-W average power

We demonstrate on a high-power 1-GHz Kerr-lens mode-locked (KLM) ytterbium (Yb):CYA laser delivering 149-fs pulses with an average power of 11.1 W. The corresponding single-pulse energy and peak power are 10.3 nJ and 60.8 kW, respectively. The mode-locking operation can be consistently sustained with root mean square (RMS) values of power fluctuations of only 0.52% for 100 min. To the best of our knowledge, this is the highest average power ever reported from a GHz femtosecond mode-locked oscillator.