Topologically protected frequency control of broadband signals in dynamically modulated waveguide arrays

In this theoretical proposal, the authors show how acousto-optic modulation can be used to generate two-dimensional topologically nontrivial band structures using one-dimensional optical waveguide arrays by frequency of light as a synthetic dimension. The scheme paves way for use standard photonic technology laser-written waveguides spectral manipulation broadband signals, both classical waves and single- or few-photon quantum wave packets.