Open AccessExperimental demonstration of metamaterial anisotropy engineering for broadband on-chip polarization beam splitting
Author(s) -
Alaine Herrero-Bermello,
Antonio Dias-Ponte,
José Manuel LuqueGonzález,
Alejandro OrtegaMoñux,
Aitor V. Velasco,
Pavel Cheben,
Robert Halir
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.389070
Subject(s) - materials science , metamaterial , optics , extinction ratio , fabrication , cladding (metalworking) , silicon on insulator , optoelectronics , polarization (electrochemistry) , beam splitter , broadband , electron beam lithography , resonator , silicon , resist , laser , physics , nanotechnology , wavelength , medicine , chemistry , alternative medicine , pathology , layer (electronics) , metallurgy
Subwavelength metamaterials exhibit a strong anisotropy that can be leveraged to implement high-performance polarization handling devices in silicon-on-insulator. Whereas these devices benefit from single-etch step fabrication, many of them require small feature sizes or specialized cladding materials. The anisotropic response of subwavelength metamaterials can be further engineered by tilting its constituent elements away from the optical axis, providing an additional degree of freedom in the design. In this work, we demonstrate this feature through the design, fabrication and experimental characterization of a robust multimode interference polarization beam splitter based on tilted subwavelength gratings. A 110-nm minimum feature size and a standard silicon dioxide cladding are maintained. The resulting device exhibits insertion loss as low as 1 dB, an extinction ratio better than 13 dB in a 120-nm bandwidth, and robust tolerances to fabrication deviations.