Plasmonic optical circuits hold great promise in reducing device footprints by orders of magnitude and enabling high device complexity. The decomposition of an arbitrary linear transformation using unitary beam splitters is well-known. However, because of the inherent lossy nature of plasmonic devices, this decomposition is not useful for the practical design of devices. In this Letter, we provide a method to design an arbitrary unitary transformation using plasmonic beam splitters, which takes into account the inherent lossy nature of plasmonic modes in the decomposition process itself, while preserving the fidelity of the transformation. We do this by selecting the loss in each arm of the beam splitters and the interconnects. We also show how this method can be extended for the case of any linear transformation by extending the singular value decomposition. This method is applicable to plasmonic and waveguide-based lossy beam splitters.

中文翻译：

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使用等离激元分束器设计光路

等离子光电路在将设备占用空间减小几个数量级并实现高设备复杂性方面具有广阔的前景。使用单一光束分离器的任意线性变换的分解是众所周知的。但是，由于等离子设备固有的损耗特性，这种分解对于设备的实际设计没有用。在这封信中，我们提供了一种使用等离激元分束器设计任意unit变换的方法，该方法考虑了分解过程本身中等离激元模态的固有损耗性质，同时保留了变换的保真度。我们通过选择分束器和互连中每个臂的损耗来实现。我们还展示了如何通过扩展奇异值分解将这种方法扩展到任何线性变换的情况。该方法适用于基于等离子体和波导的有损分束器。