Ultra-wideband and Multi-octave Tunable Millimeter Wave Generation based on Photonic Multiplication and Delay-matched Heterodyne

Millimeter wave (MMW) and terahertz technology has garnered great interest in various fields due to its wide bandwidth availability. However, generating MMW signals that concurrently possess a high frequency, extensive bandwidth, and broad tuning range presents significant challenges. We propose a photonic approach for generating MMW signals leveraging photonic multiplication and delay-matched heterodyne. This method expands the signal bandwidth through four-wave mixing (FWM) and optical sideband heterodyne beating, extending beyond traditional external modulation schemes. By adjusting the seed light frequency for FWM or modifying the electrical driving signal, the system can span a wide range of spectrum and realize multi-octave tuning of the operating frequency. Furthermore, spurious signal and distortion arising from time-delay mismatch between the sidebands are resolved and eliminated through photonic delay matching. Experimental demonstration of MMW signal generation, showcasing random frequency hopping with up to 30 GHz bandwidth across multiple bands—Ku&Ka (13-40 GHz), W (75-105 GHz), and D (140-170 GHz) bands, verifies the system's extensive tunability and broad frequency coverage. In addition, a variety of multiwaveform types were produced, including stepped frequencies, linear, and nonlinear frequency sweeps, further illustrating the system's versatile waveform configurability. This work holds potential for significant advancements in MMW communications, radar and imaging applications.