Fig. 1: Illustration of SUAD topological pumping in modulated photonic waveguides.
a Bottom-left panel: schematic of a spatially modulated SSH lattice of photonic waveguides fabricated inside a glass; Top-left panel: photograph of the fabricated sample of waveguides at the output facet (scale bar: 20 μm); Top-right panel: schematic of SSH lattice with finite sites; Bottom-right panel: spectrum schematic for illustrating two gap-protected modes occupying edges of SSH lattice. b Schematic relation between on-chip topological pumping and a specified interaction picture of gap-mode pseudospin. AD adiabatic, CD counterdiabatic. c Fidelity comparison among four topological pumping schemes in 20 waveguides with varying sample lengths, where the length value in the conventional adiabatic case (Conv.) is divided by ten. d Instantaneous propagation constants of eigenmodes relative to β1. The edge modes in the gap are hybridized into \(\left|{\phi }_{\pm }\right\rangle\). e Instantaneous distribution of excitation on each waveguide along SUAD path \(\left|{\Phi }_{-}(z)\right\rangle\). Data in c, d, e are obtained based on the full Hamiltonian \(\widehat{H}(z)\).
