Microjoule mode-locked oscillators: issues of stability and noise

Abstract

In this work, for the first time to our knowledge, stability and noise of a thin-disk mode-locked Yb:YAG oscillator operating in both negative- (NDR) and positive-dispersion (PDR) regimes have been analyzed systematically within a broad range of oscillator parameters. It is found, that the scaling of output pulse energy from 7 $\mu$J up to 55 $\mu$J in the NDR requires a dispersion scaling from -0.013 ps$^{2}$ up to -0.31 ps$^{2}$ to provide the pulse stability. Simultaneously, the energy scaling from 6 $\mu$J up to 90 $\mu$J in the PDR requires a moderate dispersion scaling from 0.0023 ps$^{2}$ up to 0.011 ps$^{2}$. A chirped picosecond pulse in the PDR has a broader spectrum than that of a chirp-free soliton in the NDR. As a result, a chirped picosecond pulse can be compressed down to a few of hundreds of femtoseconds. A unique property of the PDR has been found to be an extremely reduced timing jitter. The numerical results agree with the analytical theory, when spectral properties of the PDR and the negative feedback induced by spectral filtering are taken into account.