A novel wavelength-selective 2×2 optical switch based on a Ge2Sb2Te5 (GST)-assisted microring-resonator (MRR) is proposed. The present GST-assisted MRR consists of two access optical waveguides and an MRR coupled with a bent GST-loaded silicon photonic waveguide. The 2×2 optical switch is switched ON or OFF by modifying the GST state to be crystalline or amorphous. In particular, the microring waveguide and the bent GST-loaded waveguide are designed to satisfy the phase-matching condition when the GST is crystalline. As a result, the MRR becomes highly lossy and the resonance peak is depressed significantly. On the other hand, when it is off, there is little coupling due to the significant phase mismatching. Consequently, one has a low-loss transmission at the drop port for the resonance wavelength. In this paper, the simulation using the three-dimensional finite-difference method shows that the extinction ratio of the designed photonic switch is ∼20 dB at the resonance wavelength, while the excess losses at the through port and drop port are 0.9 dB and 2 dB. In particular, the resonance wavelength changes little between the ON and OFF states, which makes it suitable for multichannel wavelength-division-multiplexing systems.

中文翻译：

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基于 GST 辅助微环的波长选择 2×2 光开关

提出了一种基于 Ge2Sb2Te5 (GST) 辅助微环谐振器 (MRR) 的新型波长选择性 2×2 光开关。目前的 GST 辅助 MRR 由两个接入光波导和一个 MRR 与弯曲的 GST 加载硅光子波导耦合组成。2×2 光开关通过将 GST 状态修改为晶态或非晶态来开启或关闭。特别是，微环波导和弯曲的 GST 加载波导被设计成当 GST 是晶体时满足相位匹配条件。结果，MRR 变得高度有损并且共振峰显着降低。另一方面，当它关闭时，由于显着的相位失配，几乎没有耦合。因此，对于谐振波长，在分路端口处具有低损耗传输。在本文中，使用三维有限差分法的仿真表明，所设计的光子开关在谐振波长处的消光比为~20 dB，而直通端口和分出端口的超额损耗分别为0.9 dB和2 dB。特别是谐振波长在ON和OFF状态之间变化很小，这使其适用于多通道波分复用系统。