Extended Data Fig. 2: Comparison between 1 topological isolator and 5 junction isolators (UIYCI1318A10T13SF) connected in series.

Note that, even in this case, our topological isolator could have higher transmission, higher isolation, and lower group delay. The group delay time of the forward signal in the device is \(t=\frac{d\varphi }{d\omega }\), where φ represents the phase of S₂₁ and ω is the angular frequency. Consequently, a single topological isolator exhibits about 1/3 group delay compared to 5 junction isolators.