Fig. 2: TSM for the coupling of a practical three-dimensional strip waveguide (SWG) and a topological waveguide (TWG) made by silicon. | Nature Communications

Fig. 2: TSM for the coupling of a practical three-dimensional strip waveguide (SWG) and a topological waveguide (TWG) made by silicon.

From: Efficient coupling of topological photonic crystal waveguides based on transverse spin matching mechanism

Fig. 2

a Schematic of coupling structure. The width of the SWG is D. The thicknesses of the waveguides are h. The TWG is formed by air holes with radiuses of 110 nm and 55 nm according to honeycomb lattice with lattice constant of a0. A, B, and B’ are three typical positions to analyze the TS patterns. b, c Distributions of the TSs in the SWG near the position A, and in the TWG near the positions B and B’ with a separation of 0.5a0. d Changes of T and the degree of TSM β with the central position ycenter of the incident SWG at the fixed width of D = 1.2 μm. e Comparing STWGz with SSWGz when ycenter = −0.21 μm and 0.36 μm, from which the TSM can be observed intuitively.

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