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Dielectric Nanoaperture Metasurfaces in Silicon Waveguides for Efficient and Broadband Mode Conversion with an Ultrasmall Footprint
Author(s) -
Yao Chaonan,
Wang Yilun,
Zhang Jihua,
Zhang Xinliang,
Zhao Chen,
Wang Bin,
Singh Subhash C.,
Guo Chunlei
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202000529
Subject(s) - materials science , footprint , broadband , optoelectronics , silicon photonics , silicon , optics , photonics , silicon on insulator , waveguide , physics , paleontology , biology
Efficient and reliable mode converters with broadband operation and small footprint will enable high‐density silicon photonic integrated circuits to build high bitrate optical networks and handheld optical devices. Here, all‐dielectric nanoaperture metasurfaces in the silicon layer of a silicon‐on‐insulator platform are reported for mode‐order conversion with an ultrasmall footprint. Utilizing the advantages of an abrupt width change and metasurface, the mode conversion between TE 00 and TE 10 modes is realized with a conversion efficiency as high as ≈90% in simulations and 83.1% in experiments at λ = 1.55 µm within an ultrashort conversion length of about 2.42 µm, the shortest ever achieved. The incident TE 00 mode is converted to TE 10 mode with purity of more than 90% in a broadband (Δλ ≈ 230 nm) wavelength range from 1.42 to 1.65 µm. Moreover, optimizing the number, position, and dimension of nanoapertures, it is further demonstrated that the nanoaperture metasurface design can enable mode conversion between silicon waveguides of different thicknesses and different relative positions, and between TM modes.