Tunable topological wavelength division multiplexer based on lateral heterostructured edge states

The rapid development of integrated optics demands high-performance topological photonic devices, yet existing topological wavelength division multiplexing (TWDM) systems are limited by fixed bandwidth, narrow channels, and few applicable bands. This study proposes a harpoon-type high-capacity energy transmission TWDM system, introducing a tunable-mode-width large-area waveguide and a serpentine interleaved heterostructured waveguide for multi-channel separation. A precise frequency tuning method that preserves the original operating principle is also proposed. The system operates at 178.73 THz∼198.91 THz (covering the C-band), achieves a transmittance contrast of 50∼90 dB, and exhibits large-scale defect resistance, providing a comprehensive design concept for advanced TWDM systems with flexible tunability and enhanced topological protection.