Journal Article THz topological photonic integrated circuits terahertz topological photonic integrated circuits topological cavity Silicon photonics THz on‐chip cavity THz on‐chip photonics active non‐reciprocity demultiplexer multiplexer non‐reciprocal critical coupling state on‐chip integrated isolator on‐chip terahertz interconnects optothermal control photonic filter silicon THz interconnect silicon photonics supercoupled cavity terahertz 6G to XG wireless communications terahertz interconnects terahertz interfacial waveguide terahertz topological isolator topological non‐reciprocity topological supercoupling topological waveguide topological waveguides