• Chinese Optics Letters
  • Vol. 23, Issue 4, 041404 (2025)
Xinxing Guo1, Bo Liu1, Shaoshao Yu1, Qian Jing2..., Jiang Chen1, Lin Wu1, Tao Liu1,3,*, Ruifang Dong1,3,** and Shougang Zhang1,3,***|Show fewer author(s)
Author Affiliations
  • 1Key Laboratory of Time Reference and Applications, National Time Service Center, Chinese Academy of Sciences, Xi’an 710600, China
  • 2School of Science, Xi’an Shiyou University, Xi’an 710065, China
  • 3School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, China
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    DOI: 10.3788/COL202523.041404 Cite this Article Set citation alerts
    Xinxing Guo, Bo Liu, Shaoshao Yu, Qian Jing, Jiang Chen, Lin Wu, Tao Liu, Ruifang Dong, Shougang Zhang, "Time transfer over a 2061 km telecommunication fiber-optic network with single-fiber and two-wavelength approach," Chin. Opt. Lett. 23, 041404 (2025) Copy Citation Text show less
    Geographical distribution of the 2061 km field fiber link.
    Fig. 1. Geographical distribution of the 2061 km field fiber link.
    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. 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.
    Software workflow of the precision temperature control module.
    Fig. 3. Software workflow of the precision temperature control module.
    Temperature fluctuations of the board.
    Fig. 4. Temperature fluctuations of the board.
    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. 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).
    Time retention performance test during fiber interruption.
    Fig. 6. Time retention performance test during fiber interruption.
    Time difference of the 2061 km field fiber link over 400,000 s.
    Fig. 7. Time difference of the 2061 km field fiber link over 400,000 s.
    Stability (TDEV) result of time transfer over the 2061 km field fiber link.
    Fig. 8. Stability (TDEV) result of time transfer over the 2061 km field fiber link.
    Stability (ADEV) result of the accompanied 10 MHz frequency 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.
    Uncertainty sourceUncertainty contribution (ps)Uncertainty type
    Time difference measurement7.7A
    TDC7.07B
    SFPs38.0B
    FPGA1.2A
    EVDL1.4A
    Nonreciprocity from fiber6.0A
    PMD2.23B
    Sagnac12.0B
    Combined uncertainty41.8
    Table 1. Uncertainty for SFTWTT over the 2061 km Field Fiber Link
    Xinxing Guo, Bo Liu, Shaoshao Yu, Qian Jing, Jiang Chen, Lin Wu, Tao Liu, Ruifang Dong, Shougang Zhang, "Time transfer over a 2061 km telecommunication fiber-optic network with single-fiber and two-wavelength approach," Chin. Opt. Lett. 23, 041404 (2025)
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