Current optical communication systems rely on the use of wavelength division multiplexing (WDM) to keep up with the increasing data rate requirements. The wavelength demultiplexer is the key component to implement WDM systems. In this Letter, we design and experimentally demonstrate a demultiplexer based on a curved grating waveguide geometry that separates eight channels with a spacing of 10 nm (1249 GHz) around the central wavelength of 1550 nm. The fabricated device shows very low insertion loss (${\sim}{{1}}\;{\rm{dB}}$) and a crosstalk (XT) below ${-}{{25}}\;{\rm{dB}}$. This device leverages metamaterial index engineering to implement the lateral cladding on one side of the waveguide. This makes it possible to design a waveguide grating with highly directional lateral emission by operating in a regime where diffraction into the silica upper cladding is frustrated, thus suppressing losses due to off-chip radiation.

中文翻译：

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低损耗离轴弯曲波导光栅解复用器

当前的光通信系统依赖于使用波分复用 (WDM) 来满足不断增长的数据速率要求。波长解复用器是实现 WDM 系统的关键组件。在这封信中，我们设计并实验演示了基于弯曲光栅波导几何结构的解复用器，该几何解复用器在 1550 nm 的中心波长附近以 10 nm (1249 GHz) 的间隔分隔八个通道。制造的器件显示出非常低的插入损耗 ( ${\sim}{{1}}\;{\rm{dB}}$ ) 和低于${-}{{25}}\;{\的串扰 (XT) rm{dB}}$. 该设备利用超材料指数工程在波导的一侧实现横向包层。这使得设计具有高度定向横向发射的波导光栅成为可能，通过在进入二氧化硅上包层的衍射受到抑制的情况下工作，从而抑制由于芯片外辐射造成的损失。