Fig. 1. Geographical distribution of the 2061 km field fiber link.

Fig. 2. Architecture of the system for the local device, the remote device, and the relay/download devices equipped with fiber-based time transfer. DWDM, dense wavelength division multiplexing; LD, laser diode; PD, photodiode; TDC, time-to-digital converter; N, N frequency multiplier; MCU, microcontroller unit; φ1, phase of 10 MHz adjustment; φ2, phase of 1 PPS adjustment.

Fig. 3. Software workflow of the precision temperature control module.

Fig. 4. Temperature fluctuations of the board.

Fig. 5. The time difference between the systems with temperature changes before device temperature control (blue trace) and the time difference between the systems with temperature changes after device temperature control (red trace).

Fig. 6. Time retention performance test during fiber interruption.

Fig. 7. Time difference of the 2061 km field fiber link over 400,000 s.

Fig. 8. Stability (TDEV) result of time transfer over the 2061 km field fiber link.

Fig. 9. Stability (ADEV) result of the accompanied 10 MHz frequency transfer over the 2061 km field fiber link.