Characterization of phase stability and core-to-core delays in a field-deployed uncoupled-core multi-core fiber cable

We measure the relative core-core drifts of a 6.3 km installed multi-core fiber cable, reporting < 420 fs of relative drift over 9 h for all core combinations. The corresponding frequency noise is shown to be around 10^-4 and < 10^-5[Hz²/Hz] at 1 Hz and 1 mHz, respectively.