Influence and suppression of coherent Rayleigh noise in fiber-optic-based phase-stabilized microwave-frequency transmission system

Distribution of phase-stabilized microwave frequency reference over a wide area is a key technology in a variety of applications including long-baseline interferometry for radio astronomy, fundamental physics metrology and multi-static radar system. Based on the round-trip phase correction, a theory model of phase-stabilized microwave frequency reference distribution through optical fiber with opto-electronic delay locked-loop is established. Theoretical and experimental efforts are made to investigate the influence of the coherent Rayleigh-scattering noise on the system stability. Coherent Rayleigh-scattering noise not only leads to degradation of signal-to-noise rotio, but also further degrates the stabiling of remote signal by transforming phase locked loop into residual phase noise, which is the key factor of phase-stabihzed transmission. A dual wavelength transmission technology is proposed to overcome its influence, the concept by transmitting a 10 GHz microwave frequency reference over 100 km single-mode fiber is demonstrated, and the root mean square-jitter is measured under 730 fs at the remote end.