Photonic Generation of Crossed-Dual-Chirp THz LFM Signal by Single Tunable Laser

We propose a cost-effective and hardware simplified photonics-based terahertz (THz) linear frequency modulated (LFM) signal generation system. The system utilizes only a single ultra-fast wavelength tunable laser leveraging electro-optic effect combined with commercial fiber self-delay. A crossed-dual-chirp, which consists of simultaneous up-chirp and down-chirp THz LFM signals within the same 400 ns period was generated with a bandwidth of 14.6 GHz and center frequency of 284 GHz. A high chirp rate of 0.0365 GHz/ns was achieved using only a low-cost voltage controller operating at MHz frequency. This cost-effective yet high-performance solution generates crossed-dual-chirp waveforms that are expected to mitigate the Doppler error, making it suitable for high-speed target detection. The proposed system demonstrates significant advantages in practical applications, as it successfully balances performance requirements with implementation complexity.