Distribution of millimeter waves over a fiber link with high frequency stability

We present a theoretical analysis, systematic simulation, and experimental measurements for the phase noise, timing jitter, and frequency stability in the frequency distribution of millimeter waves over distant optical fiber links. The conception that the dissemination of a higher frequency reference instead of a lower one can achieve a better frequency stability is discussed and verified. We find that the system's noise floor, including thermal noise, shot noise, and any other noise from electronic components, is considered to be a fundamental limitation for a frequency reference transmission system. Benefiting from the high-precision time delay variation discrimination and accurate locking control operation, a highly stabilized reference is distributed to a remote end over a 60 km spooled fiber, achieving a frequency stability of 4 × 10^-17 at an average time 1000 s, corresponding to 23 fs of RMS timing jitter (0.01 Hz-1 MHz).