3D photonic integrated circuits are expected to play a key role in future optoelectronics with efficient signal transfer between photonic layers. Here, the optical coupling of tubular microcavities, supporting resonances in a vertical plane, with planar microrings, accommodating in‐plane resonances, is explored. In such a 3D coupled composite system with largely mismatched cavity sizes, periodic mode splitting and resonant mode shifts are observed due to mode‐selective interactions. The axial direction of the microtube cavity provides additional design freedom for selective mode coupling, which is achieved by carefully adjusting the axial displacement between the microtube and the microring. The spectral anticrossing behavior is caused by strong coupling in this composite optical system and is excellently reproduced by numerical modeling. Interfacing tubular microcavities with planar microrings is a promising approach toward interlayer light transfer with added optical functionality in 3D photonic systems.

中文翻译：

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在3D配置中垂直和平面微环之间的选择性平面外光学耦合

3D光子集成电路有望通过光子层之间的有效信号传输在未来的光电子学中发挥关键作用。在这里，探索了管状微腔的光学耦合，该耦合在垂直平面上支持共振，而平面微环则在平面内共振，以适应平面内共振。在这样的3D耦合复合材料系统中，空腔尺寸大不匹配，由于模式选择相互作用，会观察到周期性模式分裂和共振模式偏移。微管腔的轴向方向为选择性模式耦合提供了额外的设计自由度，这是通过仔细调整微管和微环之间的轴向位移来实现的。光谱抗交叉行为是由这种复合光学系统中的强耦合引起的，并且通过数值建模可以很好地重现。