Distribution of a phase-stabilized 100.02 GHz millimeter-wave signal over a 160 km optical fiber with 4.1 × 10⁻¹⁷ instability

We report a long-distance phase-stabilized millimeter-wave distribution over optical fibers, where the optical-link-induced phase noise is compensated with a high-precision photonic-generated millimeter-wave (mm-wave) voltage-controlled oscillator (VCO). The mm-wave VCO is realized based on pre-filtering and re-modulating optical spectral lines of an optical frequency comb (OFC). By adjusting the frequency spacing of the optical spectral lines extracted from the OFC, the phase error of the transmitted optical mm-wave signal can be compensated precisely. Using the mm-wave VCO, we demonstrate a distribution of a 100.02 GHz signal over spooled optical fibers and the fractional frequency instability of the system at different transmission distances is exhibited. The residual phase noise of the remote mm-wave signal after being transferred through a 160-km fiber link is measured to be −59 dBc/Hz at 1 Hz frequency offset from the carrier, and the RMS timing jitter in the frequency range from 0.01 Hz to 1 MHz reaches 62 fs. The long-term fractional frequency instability of 4.1 × 10⁻¹⁷ at 10000 s averaging time is achieved, and the maximum timing drift is within 0.93 ps (peak to peak) during 4 hours.