Silicon-on-insulator (SOI) combined with topological photonics provides on-chip integrated photonic devices CMOS-compatibility and backscattering-suppression. Here we propose a tunable SOI-based valley Hall topological insulator with two nonequivalent air holes to break inversion symmetry. Due to free-carrier excitation, the real and imaginary parts of the refractive index are modified to cause a blue-shift of bandgap and a reduction of transmittance, respectively. Based on this mechanism, we design a tunable all-optical switch with the merits of high transmittance contrast (about 23) and polarization-resolved characteristics simultaneously. Our proposed approach has potential in broadband tunable integrated photonic devices at telecommunication wavelengths.

中文翻译：

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电信波长下的可调谐绝缘体上硅谷霍尔光子晶体

绝缘体上硅（SOI）与拓扑光子学相结合，可提供片上集成光子器件CMOS兼容性和反向散射抑制。在这里，我们提出了一个可调谐的基于SOI的谷地霍尔拓扑绝缘体，该绝缘体具有两个不等价的气孔来打破反演对称性。由于自由载流子激发，折射率的实部和虚部被修改，分别导致带隙蓝移和透射率降低。基于这种机制，我们设计了一种具有高透射率对比度（约23）和偏振分辨特性的可调谐全光开关。我们提出的方法在电信波长的宽带可调集成光子设备中具有潜力。