Extended Data Fig. 7: Chiral transport quantified through the change in centre of intensity.

The angle that the centre of intensity makes to the origin, θ, is plotted as a function of propagation length for three different initial excitations (calculated using our tight-binding numerical model). a, An initial excitation created by masking a \({\mathcal{C}}=1\) topological mode (see the inset in Extended Data Fig. 4c for the full field of the initial excitation). b, An initial excitation created by masking a \({\mathcal{C}}=-1\) topological mode (see the inset in Extended Data Fig. 4b for the full field of the initial excitation). c, An untwisted fibre model is excited using the same excitation as a, to show the expected behaviour of a trivial \({\mathcal{C}}=0\) model. All models are based on our fabricated fibre parameters (a and b feature a twist rate of 837 rad/m, c is untwisted).