Architecture for high-scalability multiple-node wideband fiber-optic radio frequency distribution

We report a multi-node phase-stabilized distribution scheme for wideband radio frequency (RF) signals. By employing an optical switch, the scheme achieves quasi-lossless scaling of the number of remote sites, as the power penalty associated with the optical carrier remains largely unaffected by network expansion. Additionally, a co-located RF switch enables time-division multiplexing (TDM), allowing time-delay calibration and phase error correction to be performed simultaneously on a single wavelength. All of these are the key functions required in distributed coherent aperture systems. Phase synchronization enables the coherent superposition of the transmitted signals from each antenna, and time delay calibration allows for the controlled timing of the transfer to further enhance the signal-to-noise ratio (SNR). In terms of phase compensation, we adopt the active compensation scheme based on a phase-locked loop (PLL), which achieves precise phase correction through feedback control of an optical time delay line (OTDL). The experimental results indicate that the system has excellent phase noise suppression performance and wideband characteristics, proving that our proposed method is highly attractive for large-scale distributed antenna arrays applications.