Dave Utsav D, Bhatt Gaurang R, Rodrigues Janderson R, Datta Ipshita, Lipson Michal
Columbia Nano Initiative, Columbia University, New York, NY, USA.
Department of Electrical Engineering & Columbia Nano Initiative, Columbia University, New York, NY, USA.
Nanophotonics. 2024 Aug 7;13(21):3945-3952. doi: 10.1515/nanoph-2024-0140. eCollection 2024 Sep.
The performance of all active photonic devices today is greatly limited by loss. Here, we show that one can engineer a low loss path in a metal-clad lossy multi-mode waveguide while simultaneously achieving high-performance active photonic devices. We leverage non-Hermitian systems operating beyond the exceptional point to enable the redistribution of losses in a multi-mode photonic waveguide. Consequently, our multi-mode waveguide offers low propagation losses for fundamental mode while other higher order modes experience prohibitively high losses. Furthermore, we show an application of this non-Hermitian waveguide platform in designing power-efficient thermo-optic phase shifters with significantly faster response times than conventional silicon-based thermo-optic phase shifters. Our device achieves a propagation loss of less than 0.02 dB μm for our non-Hermitian waveguide-based phase shifters with high performance efficiency of ⋅ = 19.1 mW μs. In addition, our phase shifters have significantly faster response time (rise/fall time), ≈ 1.4 μs, compared to traditional silicon based thermo-optic phase shifters.
如今，所有有源光子器件的性能都受到损耗的极大限制。在此，我们展示了可以在金属包覆的有损多模波导中设计出低损耗路径，同时实现高性能有源光子器件。我们利用在奇异点之外运行的非厄米系统，实现多模光子波导中损耗的重新分布。因此，我们的多模波导对基模提供低传播损耗，而其他高阶模则经历极高的损耗。此外，我们展示了这种非厄米波导平台在设计功率高效的热光相移器方面的应用，其响应时间比传统硅基热光相移器快得多。对于我们基于非厄米波导的相移器，我们的器件实现了小于0.02 dB/μm的传播损耗，高性能效率为⋅ = 19.1 mW/μs。此外，与传统硅基热光相移器相比，我们的相移器具有明显更快的响应时间（上升/下降时间），≈1.4 μs。
