The data set contains the data underlying the fiber link performance evaluation published in Koke et al 2019 New J. Phys. 21 123017 (https://doi.org/10.1088/1367-2630/ab5d95). The experimental setup and the methodology used is explained in this publication. The data is stored in the Matlab(R)-native file format. Although proprietary, import of data from this file format is supported by other numerical computing environments, too. An example script for importing into Python is included. The files 'data_export_campaign_*.mat' contain the timeseries data shown in Figures 2, 3 and 4. Each of these files include variables with the following meaning: 'date_year', 'date_month', 'date_day', 'time_hour', 'time_minute', 'time_second': Timestamp of the data sample in UTC time 'inloop1' and 'inloop2': $\Lambda_{1s}$ frequency offset from nominal value in Hz of the beat signal used for stabilizing the uplink 'aom': $\Lambda_{1s}$ frequency offset from nominal value in Hz of the uplink servo acoustic-optical modulator's drive frequency 'remote1' and 'remote2': $\Lambda_{1s}$ frequency offset from nominal value in Hz of the roundtrip beat signal used for out-of-loop characterization of the frequency transfer error 'no_of_run_in_NJP_21_123017': A flag indicating the measurement runs discussed in the paper. Samples with the same non-zero integer values belong to the same measurement run. Samples marked with 0 did not enter the publication. 'DataCollected_FBAPTBLocked_CavityLocked': Result of our current monitoring of the fulfillment of the prerequisites for fiber link performance evaluation; values of 1/True indicate that data logging was active, the transfer laser was locked to the signal of the ultra-stable cavity, and the lock of the FBA(PTB) pump laser was active. The file 'data_export_uplink_downlink_aom.mat' contains the data underlying the fiber phase noise correlation analysis in Fig. 5. 'aom_uplink': $\Lambda_{1s}$ frequency offset from nominal value in Hz of the uplink servo acoustic-optical modulator's drive frequency 'aom_downlink': $\Lambda_{1s}$ frequency offset from nominal value in Hz of the downlink servo acoustic-optical modulator's drive frequency Since publication of the paper, we discovered a slight inconsistency of the nominal frequencies used in our analysis. Hence, remote fractional frequency offsets published in Koke et al 2019 New J. Phys. 21 123017 have to be corrected by subtracting fractional frequency values of 4.2E-22 (campaigns 2015-06, 2016-03, 2018-03) and 3.3E-22 (campaign 2018-12). This inconsistency does not change the conclusions drawn in the paper as these corrections are well below the associated statistical uncertainties. The correct nominal frequency values have been employed for the uploaded data set.

This work has been funded by: 1. European Union (EU), Horizon 2020, EMPIR, 18SIB06, TiFOON, Advanced time/frequency comparison and dissemination through optical telecommunication networks 2. European Union (EU), Horizon 2020, EMPIR, 15SIB05, OFTEN, Optical frequency transfer - a European network 3. Deutsche Forschungsgemeinschaft: Collaborative Research Centres 1128 'Relativistic Geodesy and Gravimetry with Quantum Sensors (geo-Q)', project A04 4. Deutsche Forschungsgemeinschaft: Excellence Cluster 2123 'QuantumFrontiers' 5. Agence Nationale de la Recherche: ANR blanc LIOM 2011-BS04-009-01 6. Agence Nationale de la Recherche: Labex First-TF ANR 10 LABX 48 01 7. Agence Nationale de la Recherche: Equipex REFIMEVE + ANR-11-EQPX-0039