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

Abstract

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

Experimental Demonstration of Multiband Comb-Enabled mm-Wave Transmission

“…In [11], the technique to generate the electro-optic comb was described, allowing the distribution of RF tones with 5-GHz spacing. However, the demonstration was done at a single center frequency of 25 GHz, generated from a single sideband filtered o-comb, and simultaneous multiband transmission was not studied.…”

Multiband Comb-Enabled mm-Wave Transmission

“…At a conceptual level, the unfiltered o-comb distribution architecture in this work can be considered as providing multiple locations and systems therein with access to a harmonic frequency synthesizer generating a predetermined set of synchronized frequencies with good phase noise properties. In [23] and [24], the technique to generate the electrooptic comb was described, allowing the distribution of RF tones with 5-GHz spacing. However, only a showcase experimental demonstration was done at a single center frequency of 25 GHz, generated from a single sideband filtered o-comb.…”