All-normal-dispersion femtosecond fiber laser with pulse energy above 20nJ

TLDR

Theoretical calculations indicate that large normal cavity dispersion can be achieved despite large nonlinear phase shifts, thanks to strong pulse shaping by spectral filtering of the chirped pulse. The study investigates the scaling and limits of pulse energy in an all‑normal‑dispersion femtosecond fiber laser. Experiments confirm that stable, self‑starting pulses with energies above 20 nJ can be generated, dechirped to <200 fs, yielding peak powers near 100 kW, in agreement with numerical simulations.

Abstract

We report a study of the scaling and limits to pulse energy in an all-normal-dispersion femtosecond fiber laser. Theoretical calculations show that operation at large normal cavity dispersion is possible in the presence of large nonlinear phase shifts, owing to strong pulse shaping by spectral filtering of the chirped pulse in the laser. Stable pulses are possible with energies of tens of nanojoules. Experimental results from Yb-doped fiber lasers agree with the trends of numerical simulations. Stable and self-starting pulses are generated with energies above 20 nJ, and these can be dechirped to <200fs duration. Femtosecond pulses with peak powers near 100kW are thus available from this simple and practical design.