We propose and demonstrate an on-chip $2\times 2$ polarization-transparent switch for simultaneously handling two-group polarization-division multiplexing (PDM) signals. By introducing the polarization-transparent power splitter/combiner (PPS/PPC), waveguide crossings such as those in conventional PDM switches can be avoided and, thus, the insertion losses and complexity of the device can be reduced. Furthermore, each input polarization tributary can be independently switched and routed thanks to the output selectivity of the PPS/PPC. Thus, not only a basic switch between the dual-group PDM signals, but also a precise four-channel-signal regrouping can be achieved, enabling a complete and non-redundant switching functionality. A polarization extinction ratio larger than 15 dB with reasonable insertion losses is experimentally observed. Clear and open eye diagrams can be obtained with less than 1 dB power penalties for all the measured paths.

中文翻译：

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具有信号重组功能的无交叉片上2×2极化透明开关

我们建议并演示片上 $\mathrm{2个}\times \mathrm{2个}$极化透明开关，用于同时处理两组极化分割多路复用（PDM）信号。通过引入极化透明的功率分配器/合并器（PPS / PPC），可以避免诸如传统PDM开关中的波导交叉，从而可以减少设备的插入损耗和复杂性。此外，由于PPS / PPC的输出选择性，每个输入极化支流都可以独立切换和路由。因此，不仅可以实现双组PDM信号之间的基本切换，而且可以实现精确的四通道信号重组，从而实现完整且非冗余的切换功能。实验观察到极化消光比大于15 dB，且插入损耗合理。