Experimental verification of topological robustness with statistical measurements by individually controlling the phase disorders in all rings. The generated random phase obeys the same uniform distribution in the range of δ [−0.5, 0.5]. A set of 100 samples with uniformly distributed random phases is chosen at δ = 0.1π in measurement. Measured transmission spectra for the disordered devices are shown as the grey background, and the spectrum for an ideal device without disorder is plotted as a blue line. In the topological edge modes the flat plateaus with high transmission are only slightly influenced, while in all other regimes severe broadening and small dips owing to obstruction from random local modes appear.
