In the past decades, photonic integrated circuits have been considered to overcome the bandwidth limitations of electronics circuits. However, photonic devices have yet to offer the same reconfigurability and programmability available in their electronics counterpart. This challenge can be addressed by integrating phase-change materials such as Ge2Sb2Te5 (GST) into photonic devices. We inserted a periodic arrangement of GST in a subwavelength grating (SWG) slot waveguide in order to have an optical filter with Bragg grating. The non-volatile and reversible phase-transition of GST, embedded in the silicon SWG slot waveguide, enables us to design a reconfigurable notch filter without static power consumption. The three-dimensional finite-difference time-domain (3D FDTD) simulation confirms that it is possible to create a 6.1 nm blueshift at the middle of the passband only by changing and controlling the phase transition of the GST. The spectral characteristics and their dependences on the geometrical parameters are investigated. The comparison of our filter with a conventional slot waveguide clearly indicates that the SWG slot waveguide provides a larger wavelength shift upon phase-transition of GST. Moreover, the SWG structure greatly improves the extinction ratio of the notch filter.

中文翻译：

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基于嵌入相变材料的亚波长光栅缝隙波导设计滤光片

在过去的几十年中，光子集成电路被认为可以克服电子电路的带宽限制。然而，光子设备尚未提供与电子设备相同的可重构性和可编程性。这一挑战可以通过集成 Ge 等相变材料来解决2锑2碲5(GST) 进入光子器件。我们在亚波长光栅 (SWG) 狭缝波导中插入了 GST 的周期性排列，以便获得带有布拉格光栅的滤光器。GST 的非易失性和可逆相变嵌入在硅 SWG 槽波导中，使我们能够设计一种可重新配置的陷波滤波器，而不会产生静态功耗。三维有限差分时域 (3D FDTD) 仿真证实，仅通过改变和控制 GST 的相变，就有可能在通带中间产生 6.1 nm 的蓝移。研究了光谱特性及其对几何参数的依赖性。我们的滤波器与传统槽波导的比较清楚地表明，SWG 槽波导在 GST 相变时提供更大的波长偏移。此外，SWG结构大大提高了陷波滤波器的消光比。