Pulse formation and spectral broadening in continuous-wave optical parametric oscillator with dispersion control

We report the initiation of pulse formation and significant spectral broadening in a continuous-wave (cw)-pumped optical parametric oscillator (OPO) in a degenerate doubly resonant oscillator (DRO) cold cavity under group-delay dispersion (GDD) compensation. The analysis of temporal, phase, and spectral domains is performed using coupled-wave equations and the Split-Step Fourier method. With GDD compensation, in the steady state, the temporal output exhibits characteristics indicative of an incipient stage of pulse formation, while the spectral density shows an approximately sixfold increase compared to that of a conventional DRO. Furthermore, the influence of key OPO parameters such as input pump power, crystal length, cavity length detuning, pump phase fluctuations, temperature instability, and third-order dispersion on the temporal and spectral characteristics of the cw GDD-compensated DRO is studied, highlighting the robustness and stability of the system.