2021/05/31 by T. T. D. Dinh, Thi Thuy Duong Dinh, Dinh, T. T. D. +29
Engineering · Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystals and Applications #Photonic and Optical Devices #Plasmonic and Surface Plasmon Research #physics.optics
paper · pdf · doi:10.48550/arxiv.2105.14929
arxiv created 2021/05/31 · openalex publication_date 2021/05/31 · arxiv updated 2021/06/01 · openalex created_date 2021/06/22 · openalex updated_date 2026/07/28
Flexible control of the modal confinement in silicon photonic waveguides is an appealing feature for many applications, including sensing and hybrid integration of active materials. In most cases, strip waveguides are the preferred solution to maximize the light interaction with the waveguide surroundings. However, the only two degrees of freedom in Si strip waveguides are the width and thickness, resulting in limited flexibility in evanescent field control. Here, we propose and demonstrate a new strategy that exploits metamaterial engineering of the waveguide core and cladding to control the index contrast in the vertical and horizontal directions, independently. The proposed dual-material geometry yields a substantially increased calculated overlap with the air (0.35) compared to the best-case scenario for a strip waveguide (0.3). To experimentally demonstrate the potential of this approach, we have implemented dual-metamaterial ring resonators, operating with the transverse-magnetic polarized mode in 220-nm-thick waveguides with air as upper-cladding. Micro-ring resonators implemented with strip and dual-metamaterial waveguides exhibit the same measured quality factors, near 30,000. Having similar measured quality factors and better calculated external confinement factors than strip waveguides, the proposed dual-metamaterial geometry stands as a promising approach to control modal confinement in silicon waveguides.