Accelerating Thouless pump in bilayer integrated waveguide lattices

Abstract The Thouless pump refers to the quantized transport of a one-dimensional system under cyclic motion of the system parameters without external forces. This phenomenon has a first Chern class topological invariant and typically requires a slow evolution to meet the adiabatic condition, which imposes a constraint on the system's compactness. In this study, we propose a method to accelerate the Thouless pump in an optical system that consists of bilayer integrated silicon waveguides operating at telecommunication wavelengths. The bilayer system's effective long-range couplings allow the adiabatic criteria to persist even with a rapid parameter evolution speed. As a result, the adiabatic pump evolution can be significantly sped up without violating the topological nature. This approach challenges traditional notions and promises a feasible and powerful compact platform for quasi-3D photonic integration at the nanoscale, enabling the realization of complex topological physics and novel on-chip photonic devices.