Lai Hsuan, Kuo Tzu-Ning, Xu Jia-Yi, Hsu Shih-Hsiang, Hsu Yi-Cheng
Department of Electronic Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan.
Department of Biomechatronics Engineering, National Pingtung University of Science and Technology, 1 Shuefu Rd., Neipu 91201, Pingtung, Taiwan.
Micromachines (Basel). 2022 Jun 10;13(6):922. doi: 10.3390/mi13060922.
In recent years, silicon-on-insulator substrates have been utilized for high-speed and low-power electronic components. Because of the high refractive index contrast of the silicon wire, its photonic device footprint can be significantly reduced. Moreover, the silicon photonic process is compatible with a complementary metal-oxide-semiconductor fabrication, which will benefit the high-density optoelectronic integrated circuits development. Researchers have recently proposed using the microring resonator (MRR) for label-free biosensing applications. The high-quality factor caused by the substantial electric field enhancement within the ring makes the MRR a good candidate for biomolecule detection under low analyte concentration conditions. This paper proposes an MRR chip to be a biosensor on the silicon platform through the relative displacement between the spatial ring-down interferograms at various cladding layers. The higher-order ring-down of the spatial interference wave packet will enhance the biosensing sensitivity after optimizing the coupling, MRR length, and the optical source bandwidth at the fixed optical waveguide loss. Finally, a typical sensitivity of 642,000 nm per refractive index unit is demonstrated under 0.1 μW minimum optical power detection for an MRR with a 100 μm radius. Higher sensitivity can be executed by a narrow bandwidth and lower silicon wire propagation loss.
近年来，绝缘体上硅衬底已被用于高速和低功耗电子元件。由于硅线的高折射率对比度，其光子器件的占地面积可以显著减小。此外，硅光子工艺与互补金属氧化物半导体制造工艺兼容，这将有利于高密度光电子集成电路的发展。研究人员最近提出将微环谐振器（MRR）用于无标记生物传感应用。环内显著的电场增强导致的高品质因数，使MRR成为低分析物浓度条件下生物分子检测的良好候选者。本文提出通过不同包层处空间衰荡干涉图之间的相对位移，将MRR芯片作为硅平台上的生物传感器。在固定光波导损耗的情况下，优化耦合、MRR长度和光源带宽后，空间干涉波包的高阶衰荡将提高生物传感灵敏度。最后，对于半径为100μm的MRR，在0.1μW最小光功率检测下，展示了每折射率单位642,000nm的典型灵敏度。通过窄带宽和更低的硅线传播损耗可以实现更高的灵敏度。
