We demonstrated an ultra-broadband dual-polarization power splitter based on silicon subwavelength gratings (SWGs). Multimode interference (MMI) couplers based on SWG are utilized for power splitting. SWGs with different orientations are combined to form a taperized hetero-anisotropic slab, which contains single mode for TE light but multimode for TM light. Such configuration is utilized to make it possible to design the coupling length of TE light and TM light separately. The geometry parameters such as numbers of periods and duty cycles for the SWGs are engineered to make the two-fold images of different wavelengths and two polarizations located at the same position, which will result in low loss and large bandwidth. Both the simulation and measurement results show that the proposed device can work over a large bandwidth of 420 nm (1.26 ~ 1.68 μm) with loss lower than 1 dB. The footprint of the proposed device is quite small (18.4 μm × 2.8 μm).

中文翻译：

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基于硅亚波长光栅的超宽带双偏振功率分配器


我们展示了一种基于硅亚波长光栅（SWG）的超宽带双偏振功率分配器。基于 SWG 的多模干扰 (MMI) 耦合器用于功率分配。不同方向的SWG组合形成锥形异质各向异性板，其中包含TE光的单模和TM光的多模。利用这种配置使得可以分别设计TE光和TM光的耦合长度。 SWG 的周期数和占空比等几何参数经过精心设计，可以使不同波长和两个偏振的两倍图像位于同一位置，从而实现低损耗和大带宽。仿真和测量结果表明，该器件可以在420 nm（1.26 ~ 1.68 μm）的大带宽上工作，损耗低于1 dB。该器件的占地面积非常小（18.4 μm × 2.8 μm）。