Abstract
High frequency microwave, spanning up to terahertz frequency, is pivotal for next-generation communication, sensing and radar. However, it faces fundamental noise limitations when frequency is pushed towards such boundary of conventional electronic technologies. Photonic microwave generation, particularly Kerr-comb-based microwave source, benefits from high frequency operation but still suffers from phase noise constraints. Here we overcome this drawback by developing a compact, electrically-driven Kerr comb system that achieves near quantum-limited phase noise for microwave synthesis up to 384 GHz. Leveraging high-Q fiber Fabry-Perot resonators and optimized noise modeling under limited pump power, we demonstrate ultra-low phase noise performances of -133 dBc/Hz (10.1 GHz) and -95 dBc/Hz (300 GHz) at 10 kHz offset, approaching quantum noise limits. This breakthrough enables 64QAM modulation in terahertz wireless communication and record 240 Gbps data rate without need for carrier phase estimation. Our device can serve as a key building block for the future information technology.