Photonic integrated resonators have advantages over traditional benchtop cavities in terms of size, weight, and cost with the potential to enable applications that require spectrally pure light. However, integrated resonators suffer from temperature-dependent frequency variations and are sensitive to external environmental perturbations, which hinders their usage in precision frequency applications. One solution is to use interrogation of the cavity temperature through dual-mode optical thermometry (DMOT) by measuring the shift of the resonance frequency difference between two polarization or optical frequency modes. Yet this approach has only been demonstrated in bulk-optic whispering gallery mode and fiber resonators. In this paper, we implement dual-mode optical thermometry in an ultra-high $Q$ integrated silicon nitride resonator. A dual-mode resonance frequency difference temperature sensitivity of ${188}\;{\pm}\;{15}\;{\rm MHz/K}$ is measured. We demonstrate feedforward DMOT frequency correction that, under an applied external temperature ramp, is able to reduce the optical frequency change to 0.31 kHz/s as compared to an uncorrected 10.03 kHz/s, a factor of ${30} \times$ reduction. These results show promise for on-chip frequency correction solutions for quantum, metrology, atomic, and coherent optical communications applications.

中文翻译：

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带有双模光学测温的集成参考腔，用于频率校正

光子集成谐振器在尺寸、重量和成本方面优于传统的台式腔，有可能实现需要光谱纯光的应用。然而，集成谐振器会受到温度相关频率变化的影响，并且对外部环境扰动很敏感，这阻碍了它们在精密频率应用中的使用。一种解决方案是通过测量两个偏振或光频模式之间的谐振频率差的偏移，通过双模光学测温 (DMOT) 来询问腔体温度。然而，这种方法仅在体光回音壁模式和光纤谐振器中得到证明。在本文中，我们在超高$Q$ 中实现了双模光学测温集成氮化硅谐振器。测得双模谐振频差温度灵敏度${188}\;{\pm}\;{15}\;{\rm MHz/K}$。我们展示了前馈 DMOT 频率校正，在施加的外部温度斜坡下，与未校正的 10.03 kHz/s 相比，能够将光频率变化降低至 0.31 kHz/s，减少了${30}\times$ 的一个因素。这些结果显示了用于量子、计量、原子和相干光通信应用的片上频率校正解决方案的前景。