We present a versatile technique for modal phase-matched second-harmonic generation in a waveguide, which relies on the incident electromagnetic field having transverse wavevector components on the input facet of the waveguide. Such a requirement is satisfied by using an angular-coupling arrangement, which allows for the excitation of modes having an odd spatial distribution that contribute to modal phase-matched second-harmonic generation. The strength of the second-harmonic signal is directly related to the angle at which the incident field is coupled into these modes. This is critical for on-chip nonlinear frequency conversion processes in the areas of optical communication, optical computing, and quantum computing.

中文翻译：

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横向波矢量投影在波导中进行相位匹配的频率转换

我们提出了一种用于波导中模态相位匹配二次谐波生成的通用技术，该技术依赖于在波导输入面上具有横向波矢量分量的入射电磁场。通过使用角度耦合装置可以满足这样的要求，该方式允许激发具有奇数空间分布的模式，这些模式有助于模态相位匹配的二次谐波产生。次谐波信号的强度与入射场耦合到这些模式的角度直接相关。这对于光通信，光计算和量子计算领域的片上非线性频率转换过程至关重要。