发表机构
NTT Research, Inc.; Cornell University（NTT研究所; 康奈尔大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出基于近简并三波混频的和频断层扫描（SFT）方法，用于高通量表征二阶非线性波导的色散与纵向相位失配，并在PPLN波导上验证其快速有效性。
AI 中文摘要
波长尺度非线性波导的最新发展凸显了对新诊断方法的需求，这些方法需同时表征波导色散和制造引起的空间不均匀性。虽然紧束缚波导能够实现紧凑且高效的非线性器件，但纳米尺度的波导不均匀性可能限制有效相互作用长度和转换效率。在本工作中，我们建立了一种基于近简并三波混频的二阶非线性波导高通量诊断方法，以下称为和频断层扫描（SFT）。与基于二次谐波产生的传统诊断方法相比，SFT产生二维传递函数，使得色散阶次能够与纵向相位失配变化分开表征。我们使用市售PPLN波导验证了该技术，并表明SFT能够恢复相互作用波之间的群速度失配、基频波的群速度色散以及纵向相位失配轮廓的低阶多项式近似。SFT避免了相位敏感或空间分辨测量的实验复杂性，使得单个波导的表征可在数秒内完成。
英文摘要
The recent development of wavelength-scale nonlinear waveguides highlights the need for new diagnostic methods that characterize both waveguide dispersion and fabrication-induced spatial inhomogeneities. While tightly confining waveguides enable compact and highly efficient nonlinear devices, nanometer-scale waveguide nonuniformities can limit the effective interaction length and conversion efficiency. In this work, we establish a high-throughput diagnostic method for second-order nonlinear waveguides based on near-degenerate three-wave mixing, hereafter referred to as sum-frequency tomography (SFT). In contrast with conventional diagnostics based on second-harmonic generation, SFT produces two-dimensional transfer functions that allow dispersion orders to be characterized separately from longitudinal phase-mismatch variations. We validate this technique using commercially available PPLN waveguides and show that SFT recovers the group-velocity mismatch between the interacting waves, the group-velocity dispersion of the fundamental, and a low-order polynomial approximation of the longitudinal phase-mismatch profile. SFT avoids the experimental complexities of phase-sensitive or spatially resolved measurements, enabling the characterization of individual waveguides in seconds.
Comments12 pages, 6 figures
