The performance analysis on phase change material germanium-antimony-tellurium-Ge2Sb2Te5 (GST)-assisted silicon waveguide-based non-volatile 1 × 2 and 2 × 2 switches are proposed. The designed structure contains a hybrid silicon waveguide and a regular silicon waveguide. By perfectly choosing the design considerations of the proposed switches, the power of transverse electric mode is coupled and shifted to cross port as an output at the amorphous state of GST (aGST), and for the crystalline state of GST (cGST), the input mode passes through the bar port as an output. The performances of the switches are evaluated by numerical calculations with the help of mode analysis of 2D finite-element method (FEM), and it is further verified by 3D finite-difference time-domain method (FDTD). For the 1 × 2 and 2 × 2 proposed switches, the obtained insertion loss (IL) of both phases of GST is <1 dB. For 1 × 2 switch design, the calculated cross-talk (CT) and extinction ratio (ER) are −31.32 and 31.31 dB, respectively at aGST state and for the cGST state, the values of CT and ER are −20.77 and 20.73 dB at 1550-nm operating wavelength. Similarly, for 2 × 2 switch design, the observed CT and ER are −32.7 and 32.69 dB, correspondingly at aGST state and for the cGST state; they are −11.98 and 11.71 dB, respectively. An additional optimization is realized via variations in the wavelength, GST width, and the coupling gap with the help of FEM analysis. Hence, broadband (80 nm) and ultracompact (∼20 μm) switches are proposed with low IL, high ER, and low CT, which can be suitable for reconfigurable optical interconnects, optical field-programmable gate array applications, microwave photonics, and quantum computing.

中文翻译：

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Ge ₂ Sb ₂ Te ₅辅助可重构非对称定向耦合器开关的数值研究

提出了基于相变材料锗-锑-碲-Ge2Sb2Te5（GST）辅助硅波导的非易失性1×2和2×2开关的性能分析。设计的结构包含混合硅波导和常规硅波导。通过完美选择拟议开关的设计考虑，横向电模式的功率在GST的非晶态（aGST）耦合并转移到交叉端口作为输出，而对于GST的晶体态（cGST）则输入模式通过条形端口作为输出。借助2D有限元方法（FEM）的模式分析，通过数值计算来评估开关的性能，并通过3D有限差分时域方法（FDTD）对其进行进一步验证。对于建议的1×2和2×2开关，GST的两个相位的插入损耗（IL）均小于1 dB。对于1×2开关设计，在aGST状态下计算出的串扰（CT）和消光比（ER）分别为-31.32和31.31 dB，对于cGST状态，CT和ER的值分别为-20.77和20.73 dB在1550纳米工作波长下。同样，对于2×2开关设计，在aGST状态和cGST状态下，观察到的CT和ER分别为-32.7和32.69 dB。它们分别是-11.98和11.71 dB。借助FEM分析，可通过波长，GST宽度和耦合间隙的变化实现其他优化。因此，提出了具有低IL，高ER和低CT的宽带（80 nm）和超紧凑（〜20μm）开关，它们适用于可重配置的光学互连，光现场可编程门阵列应用，