Optical mode enabled manipulation of topological phase in waveguide-based scattering networks

Topologies in scattering networks are governed by certain parameters that allow manipulation of their topological phases. The authors propose here a scheme to control topological phases using the waveguide mode as a controlling means. They experimentally validate this with a ring optical-waveguide device, demonstrating that changing the mode switches the robust interface state's direction, proving that the network's topological phase can be controlled by specific waveguide modes.