Integrated photonic ultrawideband real-time spectrum sensing for 6G wireless networks

Real-time spectrum sensing (RT-SS) is an essential technology for the upcoming sixth-generation (6G) networks, enabling dynamic spectrum management to support emerging integrated sensing and communication (ISAC) applications. However, conventional electronic and photonic RT-SS solutions face challenges in achieving ultrawide measurement range, compact size, and low latency, simultaneously. Here, we demonstrate an integrated photonic RT-SS system covering microwave to sub-terahertz bands on a thin-film lithium niobate (TFLN) platform. The TFLN chip integrates a broadband electro-optic (EO) modulator for signal loading, an EO microring filter bank for high-speed parallel frequency-to-time mapping, and an EO comb for channel referencing. The system achieves an analysis bandwidth of 57.5 GHz and measurable frequency up to 120 GHz, at a low latency of  < 110 ns. The RT-SS system is further validated through a proof-of-concept ISAC demonstration, where a radar adaptively accesses underutilized spectral regions for high-quality ranging under dynamic communication interferences. Our work provides a compact solution for high-efficiency spectrum management in 6G ISAC networks.