An ultra-compact broadband 2 × 2 3 dB power splitter is proposed and demonstrated by utilizing a subwavelength- grating (SWG)-assisted asymmetric directional coupler. In the present design, a subwavelength grating is inserted into the straight coupling region of an asymmetric directional coupler, so that the refractive index and the dispersion properties of this structure are engineered for achieving an ultra-broad bandwidth and an ultra-compact footprint. For the present power splitter with a straight coupling region as short as 5.25 μm, the bandwidth is as large as 300 nm (1400∼1700 nm) for achieving an imbalance of <0.4 dB and an excess loss of <0.33 dB for the fundamental transverse electrical (TE) mode. The fabricated splitter works well with an imbalance less than 0.5 dB and with an excess loss less than 1 dB in a broad wavelength-band from 1450 to 1650 nm.

中文翻译：

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使用亚波长光栅辅助非对称定向耦合器的超紧凑宽带 2×2 3 dB 功率分配器

通过利用亚波长光栅 (SWG) 辅助的非对称定向耦合器，提出并演示了一种超紧凑的宽带 2 × 2 3 dB 功率分配器。在本设计中，亚波长光栅被插入到非对称定向耦合器的直耦合区域，从而设计该结构的折射率和色散特性，以实现超宽带宽和超紧凑占地面积。对于目前直耦合区域短至5.25 μm的功率分配器，带宽大至300 nm（1400∼1700 nm），以实现<0.4 dB的不平衡和<0.33 dB的基本横向损耗电 (TE) 模式。制造的分路器在不平衡小于 0 的情况下运行良好。