Journal Article terahertz MEMS 6G communication Silicon photonics THz on‐chip cavity THz photonics THz topological integrated circuits (TTICs) THz topological photonic integrated circuits YBCO active metamaterials demultiplexer dual-channel switching germanium antimony telluride high-temperature superconductors loss engineering metamaterials metasurfaces multiplexer non-volatile photonics on-chip modulators on‐chip terahertz interconnects optothermal control phase transition phase‐change photonic filter photonics quantum and topological photonics supercoupled cavity terahertz 6G to XG wireless communications