Integrated Raman lasers have been well explored using silica and silicon platforms for decades. A well‐known equation with negligible nonlinear losses is employed for predictions of Raman lasing threshold powers in critically coupled cavities. However, nonlinear losses are known to be highly detrimental to silicon devices. Herein, for the first time, including the effects of linear loss, nonlinear losses, and cavity design, a new general equation that predicts the onset of Raman lasing in a cavity is derived and validated experimentally. Generally, a cavity with a small effective area, a short length, and high quality factors (Qs) at both pump and Stokes wavelengths can lase at relatively low pump power. This theory is verified by the experimental results with sub‐milliwatt threshold powers in 2.8 mm long multimode cavities with different Qs at different pump wavelengths. The derived Raman gain coefficients from the measurements follow the scaling rules of Raman gain. This work advances the understanding of Raman lasing in high‐Q multimode cavities. It also shows that Raman lasing at O/S‐band is possible in racetrack resonators without needing any reverse bias and the broad operation wavelength is promising for single‐chip silicon devices operating at all communication bands.

中文翻译：

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多模硅赛马场谐振器中的拉曼激光

数十年来，使用二氧化硅和硅平台已对集成拉曼激光器进行了深入研究。众所周知，非线性损耗可忽略不计的方程用于预测临界耦合腔中的拉曼激光阈值功率。然而，已知非线性损耗对硅器件非常有害。在此，首次包括线性损失，非线性损失和腔设计的影响，得出了一个新的通用方程，该方程可预测腔中拉曼激光的发作，并进行实验验证。通常，在泵浦和斯托克斯波长处具有较小有效面积，较短长度和高质量因子（Qs）的腔体会以相对较低的泵浦功率发射激光。实验结果用2兆瓦以下的阈值功率验证了该理论。8毫米长的多模腔，在不同的泵浦波长下具有不同的Qs。从测量得出的拉曼增益系数遵循拉曼增益的缩放规则。这项工作提高了对高Q多模腔中拉曼激光的理解。这也表明，在赛道谐振器中可以在O / S波段进行拉曼激射，而无需任何反向偏置，并且宽工作波长有望在所有通信频带下工作的单芯片硅器件。