Diffraction gratings that redirect light propagating in a channel waveguide to an on-chip slab are emerging as important building blocks in integrated photonics. Such distributed Bragg deflectors enable precise shaping of slab confined beams for a variety of applications, including wavelength multiplexing, optical phased array feeding, and coupling interfaces for on-chip point-to-point communications. However, these deflectors suffer from significant losses caused by off-chip radiation. In this Letter, we show, for the first time, to the best of our knowledge, that off-chip radiation can be dramatically reduced by using the single-beam phase matching condition and subwavelength metamaterial refractive index engineering. We present a deflector design with losses below 0.3 dB, opening a path toward new applications of distributed Bragg deflectors in integrated photonics.

中文翻译：

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使用特异材料设计的布拉格偏转器，从波导模式到芯片上光束的高效转换

将在通道波导中传播的光重定向到片上平板的衍射光栅正在成为集成光子学中的重要组成部分。这种分布式布拉格偏转器可以精确成形板状约束光束，以用于各种应用，包括波长复用，光学相控阵馈电以及片上点对点通信的耦合接口。然而，这些偏转器遭受由芯片外辐射引起的显着损失。在这封信中，我们首次表明，据我们所知，通过使用单光束相位匹配条件和亚波长超材料折射率工程，可以显着降低片外辐射。我们提出了一种导流板设计，其损耗低于0.3 dB，