Coupling $S{i}_3{N}_4$ waveguide to SOI waveguide using transformation optics

Abstract

Silicon nitride ($S{i}_3{N}_4$) planar waveguide platform combined with silicon-on-insulator (SOI) devices offer a whole new generation of system-on-chip applications. Therefore, efficient coupling of an $S{i}_3{N}_4$ waveguide to an SOI waveguide is essential. We present a coupler to interface a 1.8 $\mu m$-wide $S{i}_3{N}_4$ waveguide to a 0.5 $\mu m$-wide SOI waveguide based on the focusing property of the Luneburg lens. In order to match the refractive indices of the waveguides with the edges of the lens, one side of the lens is flattened with quasi-conformal transformation optics. The designed coupler is implemented by graded photonic crystals. The three-dimensional numerical simulations indicate that the 1.93 $\mu m$-long coupler has an average coupling loss of 0.13 dB in the C-band.

References in corpus (14)

• All-optical signal processing platforms for CMOS compatible integrated nonlinear optics
• Nanophotonic Pockels modulators on a silicon nitride platform
• Luneburg lens in silicon photonics
• Photonic crystal waveguide intersection design based on Maxwell's fish-eye lens
• Multilayered Maxwell's fisheye lens as waveguide crossing
• Polygonal Maxwell's fisheye lens via transformation optics as multimode waveguide crossing
• Multimode waveguide crossing based on square Maxwell's fisheye lens
• Photonic crystal waveguide crossing based on transformation optics
• Low-index contrast waveguide bend based on truncated Eaton lens implemented by graded photonic crystals
• Polymer multimode waveguide bend based on a multilayered Eaton lens
• Ultrashort waveguide tapers based on Luneburg lens
• Maxwell's fisheye lens as efficient power coupler between dissimilar photonic crystal waveguides
• 3$\times$3 Slot waveguide crossing based on Maxwell's fisheye lens
• Coupling silica waveguides to photonic crystal waveguides through multilayered Luneburg lens

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