Ultra-Short Pulse Generation From Optical Parametric Oscillators With a Cavity-Length Detuning

We report that the pulse compression mechanism in cavity-length-detuned optical parametric oscillators (OPOs) could be used to generate high-quality, soliton-like optical pulses with sub-100 fs duration. By numerical simulations, we illustrated the pulse and spectral evolution in an OPO with respect to cavity-length detuning, including central wavelength shift, spectral broadening and pulse compression. Experimentally, from an OPO pumped by 180 fs pulses, we obtained 42 fs signal pulses with a time-bandwidth product of 0.32. At elevated pump powers, the formation of multiple pulses was observed. Nonetheless, we demonstrated that the high-quality optical pulses could be obtained by simply slightly increasing the cavity-length detuning.