By identifying the similarities between the coupled-wave equations and the parametrically driven nonlinear Schrdinger equation, we for the first time unveil the existence condition of quadratic solitons in continuous-wave pumped singly resonant degenerate optical parametric oscillators (SR-DOPOs). Compared to the previously explored doubly resonant DOPOs, quadratic solitons in SR-DOPOs are advantageous in their robustness against perturbations induced by dispersion of the effective third-order nonlinearity and temporal walk-off between the signal and the pump. Terahertz comb bandwidth and femtosecond pulse duration are attainable in an example periodically poled lithium niobite waveguide resonator in the short-wave infrared. The working principle can be extended to other material platforms, making it a competitive ultrashort pulse and broadband comb source architecture at the mid-infrared.

中文翻译：

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单共振简并退化光参量振荡器中的二次孤子

通过确定耦合波方程与参数驱动的非线性薛定inger方程之间的相似性，我们首次揭示了连续波泵浦单谐振简并退化光学参量振荡器（SR-DOPO）中二次孤子的存在条件。与先前探讨的双共振DOPO相比，SR-DOPO中的二次孤子在鲁棒性方面具有优势，可抵抗有效三阶非线性和信号与泵之间的时间离散所引起的扰动。在短波红外中的周期性极化的铌铌酸锂波导谐振器的示例中，可获得太赫兹梳状带宽和飞秒脉冲持续时间。工作原理可以扩展到其他物料平台，