2025年3月6日，国防科技大学徐平研究团队在《物理评论A》杂志发表论文，他们的最新研究实现了硅芯片上的耦合模相位匹配。

相位匹配是频率转换和全光处理的经典非线性过程以及量子光源生成的自发参量过程的核心。在这项工作中，研究组通过实验证明了由绝缘体上硅（SOI）芯片上的两个并联耦合波导设计的耦合模相位匹配（CMPM），将转换光束和纠缠光子扩展到S带和L带。他们测量了波长转换的光谱和效率，成功验证了所设计的CMPM方案。并进一步测量了基于自发四波混频的双光子的对生成率，其特征是带宽窄，与理论模拟一致。

通过利用耦合系统的偶数和奇数超模的组合，并通过在两个波导之间设计适当的耦合间隙进行调谐，可以实现多种CMPM条件。CMPM可以将FWM非线性过程从O带扩展到U带，甚至扩展到中频，在很大程度上丰富了工作波长。此外，CMPM具有离散频带窄带宽，这将大大提高频率的编码密度和产生光子的光谱纯度。此外，该方法可以很容易地扩展到氮化硅等各种材料，无需进行相位匹配的色散工程。

附：英文原文

Title: Coupled-mode phase matching on a silicon chip

Author: Chao Wu, Pingyu Zhu, Miaomiao Yu, Weihong Luo, Qilin Zheng, Kaikai Zhang, Yingwen Liu, Ping Xu

Issue&Volume: 2025/03/06

Abstract: Phase matching lies at the heart of the classical nonlinear process for frequency conversion and all-optical processing, as well as the spontaneous parametric process for the quantum light sources generation. In this work, we experimentally demonstrate the coupled-mode phase-matching (CMPM) engineered by the two-paralleled-coupled waveguides on a silicon-on-insulator (SOI) chip, extending the converted beam and entangled photons to the S band and L band. We measure the spectrum and efficiency of wavelength conversion, which successfully validates the designed CMPM scheme. We further measure the pairs generation rate of the biphoton based on the spontaneous four-wave mixing, which features a narrow bandwidth consistent well with the theoretical simulations. Multiple CMPM conditions can be achieved by exploiting the combinations of even and odd supermodes of the coupled system and tuned by designing a proper coupling gap between the two waveguides. The CMPM can extend the FWM nonlinear process ranging from the O band to the U band and even the midinfrared, enriching the working wavelength to a large extent. In addition, the CMPM features a discrete-band narrow bandwidth, which will greatly enhance the encoding density of frequency and the spectral purity of generated photon. In addition, our methods can be easily extended to a wide range of materials such as silicon nitride, dispensing with the dispersion engineering for phase matching.

DOI: 10.1103/PhysRevA.111.033504

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.111.033504