Ultra-fast Photonic THz Frequency Hopping Driven by Reflection-type Transversal Filter Laser for Anti-jamming Terahertz Communications

In future 6G networks, photonic-based terahertz (THz) frequency-hopping (FH) spread spectrum systems are expected to evade jamming attacks by hopping across their wide bandwidth to secure carrier frequencies. However, the hopping range and hopping speed of current THz FH systems are constrained by the tuning capability of conventional thermo-optically wavelength tunable lasers, which is typically operated at millisecond-range transition time. This Letter proposed and demonstrated an anti-jamming THz FH system with a fast transition time of less than 49 ns by harnessing an ultra-fast wavelength-tunable laser leveraging the electro-optic effect. The system performed pseudo-random frequency hopping across three carrier frequencies from 240 GHz to 320 GHz with 40 GHz spacing, reaching <b>5 × 10⁶</b> hops/s for enhanced jamming immunity. Additionally, we demonstrated the feasibility of 10 Gbit/s on-off keying (OOK) communication in the proposed system.