Doughan Isaac, Oyemakinwa Kehinde, Ovaskainen Olli, Roussey Matthieu
Department of Physics and Mathematics, Center for Photonics Sciences, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland.
Nanomaterials (Basel). 2023 Jan 24;13(3):469. doi: 10.3390/nano13030469.
This article proposes a novel demonstration of a low-loss polymer channel hybridized with a titania core leading to a nano-waveguide elongated in the normal direction to the substrate. It is aimed at using the quasi-transverse magnetic (TM) mode as the predominant mode in compact photonic circuitry. A detailed design analysis shows how a thin layer of a higher-refractive index material in a trench within the core of the waveguide can increase the confinement and reduce the propagation losses. This thin layer, produced by atomic layer deposition, covers the entire polymer structure in a conformal manner, ensuring both a reduction of the surface roughness and a stronger field confinement. The trench can be made at any place within the polymer channel and therefore its position can be tuned to obtain asymmetric modal distribution. The waveguide is demonstrated at telecom wavelengths, although the material's properties enable operation over a large part of the electromagnetic spectrum. We measured propagation losses as low as 1.75 ± 0.32 dB/cm in a 200 nm × 900 nm section of the waveguide core. All processes being mass-production compatible, this study opens a path towards easier integrated-component manufacture.
本文提出了一种新型的低损耗聚合物通道，它与二氧化钛芯相结合，形成了一个沿垂直于衬底方向延伸的纳米波导。其目的是在紧凑型光子电路中使用准横磁（TM）模式作为主要模式。详细的设计分析表明，波导芯内沟槽中的一层高折射率材料薄层如何能够增加光场限制并降低传播损耗。通过原子层沉积制备的这一薄层以共形方式覆盖整个聚合物结构，既确保了表面粗糙度的降低，又实现了更强的场限制。沟槽可以在聚合物通道内的任何位置形成，因此其位置可以进行调整以获得不对称的模式分布。尽管该材料的特性使其能够在大部分电磁频谱范围内工作，但该波导是在电信波长下进行演示的。我们在波导芯200 nm×900 nm的截面中测得传播损耗低至1.75±0.32 dB/cm。由于所有工艺都与大规模生产兼容，这项研究为更易于制造集成组件开辟了一条道路。
