Photonic Generation of Joint Amplitude‐Frequency Modulated Waveform for THz Integrated Sensing and Communication

ABSTRACT In this letter, we present a photonic‐aided approach for generating a joint amplitude‐frequency modulated waveform, tailored for integrated sensing and communication (ISAC) in the THz band. Specifically, this THz waveform synergistically combines stepped‐frequency continuous‐wave (SFCW) with amplitude‐shift keying (ASK) to effectively mitigate spectrum congestion challenges. To validate the feasibility of this approach, we conduct a preliminary experiment utilizing an integrated tunable laser array (TLA) module and a developed uni‐traveling‐carrier photodiode (UTC‐PD) module. In this setup, a THz optical beat signal, characterized by wavelength switching, is generated by two adjacent distributed feedback laser diodes (DFB‐LDs) integrated within the TLA module; it is then subjected to intensity modulation and down‐converted to the THz band via photomixing within the UTC‐PD module. Our demonstration shows that an up‐sawtooth SFCW with a switching rate of 381 GHz/s across the 280–320 GHz range and a concurrent 2ASK transmission rate of 2 Gbit/s can be achieved, suggesting that further optimization could unlock even greater performance. In conclusion, these preliminary results underscore the efficacy of photonic techniques in achieving wide bandwidth and high integration, and highlight their potential as promising solutions for THz ISAC applications.