Synchronising Clock and Carrier Frequencies with Low and Coherent Phase Noise for 6G

Using radio over fiber techniques, we generate, transmit and receive a highly accurate 5-GHz spaced frequency comb, with carriers of extremely low phase noise. The carriers are used in an over the air transmission experiment, demonstrating lower phase noise than a commercially available PLL. The low phase noise and scalability of the design offer a new method of carrier and low-jitter clock distribution satisfying the stringent demands of future 6G systems. We demonstrate the efficacy of the method by over the air transmission of 128-QAM signal at 25 GHz. The recovered signal shows the advantage of low phase noise carriers even at received powers approaching -50 dBm