Journal Article THz topological photonic integrated circuits topological cavity THz on‐chip cavity THz on‐chip photonics active non‐reciprocity non‐reciprocal critical coupling state on‐chip integrated isolator on‐chip terahertz interconnects optothermal control silicon THz interconnect silicon photonics supercoupled cavity terahertz interfacial waveguide terahertz topological isolator terahertz topological photonic integrated circuits topological non‐reciprocity topological supercoupling topological waveguide