Observation of nonlinearity-controlled switching of topological edge states

We report the experimental observation of periodic switching topological edge states between two dimerized fs-laser written waveguide arrays. Switching occurs due to overlap modal fields from forbidden gap, when they are simultaneously present in arrays brought into close proximity. found that phenomenon for both strongly and weakly localized rate increases with decreasing spacing When contact nontopological ones, gap does not occur, while one observes either formation nearly stationary interface mode or asymmetric diffraction array depending on position initial excitation. can be controlled even completely arrested by increasing peak power input signal, as we observed different spacings.