Ultrafast optical switching using photonic molecules in photonic crystal waveguides.
Ultrafast optical switching using photonic molecules in photonic crystal waveguides.
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DOI：
10.1364/oe.23.009211
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发表时间：
2015-04
期刊：
影响因子：
3.8
通讯作者：
Yanhui Zhao;C. Qian;Kang-sheng Qiu;Yunan Gao;Xiulai Xu
中科院分区：
文献类型：
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作者：
Yanhui Zhao;C. Qian;Kang-sheng Qiu;Yunan Gao;Xiulai Xu
利用时域有限差分法和耦合模理论研究了光子晶体平板结构中光子分子与波导的耦合。在双腔光子分子中，腔模的耦合产生两个具有对称和反对称场分布的超模。当同时激发两个超模时，电场的能量在两个腔之间振荡。为了激发和探测能量振荡，我们将光子分子与两个光子晶体波导集成在一起。在耦合结构中，我们发现两个超模的品质因子可能会因为超模的场分布不同而不同。通过优化光子分子两腔之间的空气孔半径，可以使两个超模的品质因子几乎相等，波导模与两个超模之间的耦合强度也几乎相同。在这种情况下，两个腔之间的完整能量振荡可以通过一个波导中的泵浦源获得，其可以由另一个波导读出。最后，我们证明了所设计的结构可以用于超快光开关的时间尺度为几皮秒。
We study the coupling between photonic molecules and waveguides in photonic crystal slab structures using finite-difference time-domain method and coupled mode theory. In a photonic molecule with two cavities, the coupling of cavity modes results in two super-modes with symmetric and anti-symmetric field distributions. When two super-modes are excited simultaneously, the energy of electric field oscillates between the two cavities. To excite and probe the energy oscillation, we integrate photonic molecule with two photonic crystal waveguides. In coupled structure, we find that the quality factors of two super-modes might be different because of different field distributions of super-modes. After optimizing the radii of air holes between two cavities of photonic molecule, nearly equal quality factors of two super-modes are achieved, and coupling strengths between the waveguide modes and two super-modes are almost the same. In this case, complete energy oscillations between two cavities can be obtained with a pumping source in one waveguide, which can be read out by another waveguide. Finally, we demonstrate that the designed structure can be used for ultrafast optical switching with a time scale of a few picoseconds.