Generation of 49 fs, 41 MW peak power pulses from fiber laser using nonlinear compression in rod type fiber

In this paper, for the first time, of a rod-type photonic crystal fiber as the passive nonlinear element to provide the SPM induced spectral broadening at even higher energy level. Moreover, the uncompensated non-linear residual spectral phase, a crucial point for the compressed pulse quality, has been carefully studied. In this case the pulses´ spectrum broadens from 12 to 34 nm. At the output of the prism compressor, 49 fs pulses were obtained with an energy of 2 muJ. The pulses are close to the Fourier-transform limit (47 fs) with a time-bandwidth product of 0.46. The pulses were characterized by second harmonic generation frequency resolved optical gating (SHG-FROG) measurements cross checked by independent autocorrelation and spectrum measurements. The corresponding FROG trace as well as the retrieved pulse intensity and spectrum. A peak power as high as 41 MW was reached due to the very good quality of the pulses: the temporal Strehl ratio was 0.88. In conclusion, we have generated 49 fs, 2 muJ pulses at 200 kHz with an effective peak power of 41 MW using nonlinear compression based on a rod-type photonic crystal fiber and a prism compressor.