On-chip polarization splitters are key elements for coherent optical communication systems and polarization diversity circuits. These devices are often implemented with directional couplers that are symmetric for one polarization and strongly asymmetric for the other polarization. To achieve this asymmetry, highly dissimilar waveguides are used in each coupler arm, often requiring additional material layers or etch steps. Here we demonstrate polarization splitting with a directional coupler composed of two fully etched subwavelength waveguides, differing only in the tilt angle of the silicon segments. Our device exhibits deep-UV compatible feature sizes, is 14 µm long, and covers a 72 nm bandwidth with insertion losses below 1 dB and an extinction ratio in excess of 15 dB.

中文翻译：

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使用倾斜的亚波长光栅的偏振分离定向耦合器。

片上偏振分束器是相干光通信系统和偏振分集电路的关键元件。这些设备通常用定向耦合器实现，定向耦合器对于一个极化是对称的，而对于另一极化是强烈不对称的。为了实现这种不对称性，每个耦合器臂中使用了高度不同的波导，通常需要额外的材料层或蚀刻步骤。在这里，我们演示了使用由两个完全蚀刻的亚波长波导组成的定向耦合器进行的偏振分裂，仅在硅段的倾斜角上有所不同。我们的器件具有深紫外兼容的特征尺寸，长14 µm，覆盖72 nm带宽，插入损耗低于1 dB，消光比超过15 dB。