Chiral light–matter interaction is currently revolutionizing the fundamental research on light and its applications. This interaction has traditionally faced the challenges of low directionality and efficiency based on the spin–orbit interaction of light in microscopic waveguides. It is important to exploit photonic integrated circuits to efficiently engineer photonic chiral behavior. In this paper, we propose and demonstrate ultra-directional high-efficiency chiral coupling in silicon photonic circuits based on low-to-high-order mode conversion and interference. We show that the directionality of chiral coupling can, in principle, approach $\pm 1$ with circular polarization inputs by benefiting from the underlying mechanism of complete destructive and constructive interference. The efficiency of chiral coupling can exceed 70%, with negligible scattering to unguided modes, and this is considerably higher than the efficiency of conventional coupling mechanisms. Moreover, chiral silicon photonic circuits can function as perfect 3 dB power splitters for arbitrarily linear polarization inputs. These offer the possibility of on-chip chirality determination and management using photonic integrated circuits for flourishing development in chiral optics.

中文翻译：

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超定向高效手性硅光子电路

手性光与物质的相互作用目前正在彻底改变光及其应用的基础研究。基于微观波导中光的自旋轨道相互作用，这种相互作用传统上面临着方向性和效率低下的挑战。利用光子集成电路来有效地设计光子手性行为是很重要的。在本文中，我们提出并演示了基于低阶到高阶模式转换和干扰的硅光子电路中的超方向高效手性耦合。我们证明，手性偶联的方向性原则上可以接近$\pm \mathrm{1个}$受益于完全破坏性和建设性干扰的基本机制，从而实现了圆极化输入。手性耦合的效率可以超过70％，而对非引导模式的散射可以忽略不计，这比常规耦合机制的效率高得多。此外，手性硅光子电路可以用作任意线性偏振输入的理想3 dB功率分配器。这些提供了使用光子集成电路进行片上手性确定和管理的可能性，以促进手性光学器件的蓬勃发展。