On‐chip lithium niobate (LN) microresonator is regarded as a promising candidate for power clamping in second harmonic generation (SHG) owing to its high‐quality factor, small mode volume, and large nonlinear coefficient. To date, various theories have been proposed to describe the three‐wave mixing mechanism within a LN microresonator, while a comprehensive understanding of mode evolution and its impact on nonlinear frequency conversion efficiency especially for power clamping, is still limited. Here, the dual‐resonance detuning dynamics are investigated theoretically and the effect of mode chord angles on nonlinear frequency conversion efficiency is analyzed. Experimentally, two distinct power clamping points, including the normalized conversion efficiency of ≈38% mW−1 and output power of ≈1.2 mW, are separately observed in the same microresonator, consistent with the theoretical model. The results clarify the physical mechanism behind the power clamping in the observed SHG and offer a unique approach to achieving efficient and powerful SHG in LN microresonators.

中文翻译：

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片上铌酸锂微盘内产生二次谐波的功率箝位


片上铌酸锂 （LN） 微谐振器因其高品质因数高、模式体积小和非线性系数大，被认为是二次谐波产生 （SHG） 中功率钳位的有前途的候选者。迄今为止，已经提出了各种理论来描述 LN 微谐振器内的三波混频机制，而对模式演化及其对非线性频率转换效率（尤其是功率箝位）的影响的全面理解仍然有限。本文从理论上研究了双谐振失谐动力学，并分析了模弦角对非线性频率转换效率的影响。在实验中，在同一微谐振器中分别观察到两个不同的功率钳位点，包括 ≈38% mW−1 的归一化转换效率和 ≈1.2 mW 的输出功率，这与理论模型一致。结果阐明了观察到的 SHG 中功率钳位背后的物理机制，并为在 LN 微谐振器中实现高效和强大的 SHG 提供了一种独特的方法。