Experimental demonstration of time-frequency transmission in a 22.5 km 7-core fiber link

We experimentally demonstrated a 22.5 km stable optical time-frequency transmission system using 7-core fiber, achieving a time-synchronization accuracy of
$\pm 625$
ps, time stability of 5 ps, and frequency stability of
$6.23\times 10^{-14}/$
1000s, verifying the potential of multicore fibers for application in optical stable time-frequency transmission.