Optical microcavity based four-wave mixing (FWM) and its various applications, such as entangled photon pair generation, have been intensively studied in the past few years. Compared to the microring cavities that most researchers have been focusing on, here, we report the generation of FWM photons with Fabry–Perot Bragg grating cavities (FPBG) using the Si₃N₄/SiO₂ platform. By leveraging the large, nonuniform and symmetrical dispersion and tunability of our grating cavity, a unique strategy is established to compensate the strong normal dispersion of the waveguide and phase matching condition is achieved on a thin Si₃N₄ film, which is critical for efficient wavelength conversion. We develop an analytical model to optimize the nonlinear conversion efficiency of FWM, and we also introduce tapered grating in the FPBG to reduce the grating loss from 3.5 dB/cm to 0.36 dB/cm. With a 5.3 dBm pump power, the nonlinear conversion efficiency is characterized to be −37.7 dB. Our work demonstrates that FPBG is a promising on-chip platform for entangled photon pair generation and quantum communication applications.

中文翻译：

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片上法布里-珀罗布拉格光栅腔增强四波混频

在过去几年中，对基于光学微腔的四波混合（FWM）及其各种应用（例如纠缠光子对的产生）进行了深入研究。与大多数研究人员一直关注的微环腔相比，在这里，我们报道了使用Si ₃ N ₄ / SiO ₂平台通过法布里-珀罗布拉格光栅腔（FPBG）生成的FWM光子。通过利用我们光栅腔的大，非均匀且对称的色散和可调性，建立了一种独特的策略来补偿波导的强法向色散，并在薄Si ₃ N ₄上实现了相位匹配条件膜，这对于有效的波长转换至关重要。我们开发了一个分析模型来优化FWM的非线性转换效率，并且在FPBG中引入了锥形光栅，以将光栅损耗从3.5 dB / cm降低到0.36 dB / cm。泵浦功率为5.3 dBm时，非线性转换效率为−37.7 dB。我们的工作表明，FPBG是纠缠光子对生成和量子通信应用的有前途的片上平台。