Highly Stable Microwave Dissemination over Fiber with Suppressed Incoherent Rayleigh Scattering Noise

We propose and experimentally demonstrate a highly stable microwave dissemination system with suppressed incoherent Rayleigh scattering noise (RSN) in long-haul fiber links. The proposed system employs an innovative reflective architecture that selectively removes the transmitted signal component from back-reflected light while preserving the probe signal, effectively suppressing Rayleigh backscattering-induced noise. Besides, active time jitter compensation is achieved via a precision-engineered variable optical delay line (VODL), effectively stabilizing fiber link temporal characteristics. An experimental demonstration was performed. Experimental results exhibit an 11.2 dB suppression of additive phase noise at 10 kHz offset frequency in the proposed microwave dissemination link, representing significant improvement over conventional Faraday rotating mirror (FRM)-based transmission link. System characterization further reveals outstanding temporal stability, demonstrating 0.23-ps root-mean-square (RMS) delay jitter over 2000 s observation time. The fractional frequency stability of the microwave dissemination link is calculated to be 1.2 × 10^-13 @ 1s and 1.6 × 10^-15 @ 100s.