Supercontinuum generation from a quasi-stationary doubly resonant optical parametric oscillator

We report a novel, to the best of our knowledge, quasi-stationary operation-state in a femtosecond doubly resonant optical parametric oscillator (OPO). At high pump rates, a doubly resonant OPO (DRO) could evolve into a nonstationary state, and we demonstrate that through an averaging procedure, most of the power fluctuations could be suppressed, resulting in a quasi-stationary output. Moreover, the quasi-stationary DRO could be configured to generate broadband supercontinuum, with a bandwidth only limited by the parametric gain bandwidth of the nonlinear crystal. Experimentally, from a DRO based on a 3-mm-long MgO: PPLN crystal, we generated a supercontinuum with a -20dB bandwidth of 86.9 THz, covering 1.54-2.78 µm. This indeed opens up new opportunities for generating light emission with an ultra-wide bandwidth at various wavelength regions.