WDM-Based Fiber-Optic Time Synchronization Without Requiring Link Calibration

Faxing Zuo,Guiling Wu,Jianping Chen,Zufeng Chen,Liang Hu

doi:10.1109/access.2020.3003702

Faxing Zuo, Guiling Wu + Show 3 more

Open Access

https://doi.org/10.1109/access.2020.3003702

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Abstract

In this paper, we propose a fiber-optic time synchronization technique based on the bidirectional wavelength division multiplexing (WDM) transmission over a fiber link. The effect of fiber dispersion on the uncertainty of the system is effectively suppressed by properly allocating the forward and backward wavelength maps. Thus, only an initial easy-to-implement calibration in a back-to-back configuration instead of multiple complicated link calibrations is required. To compensate the propagation delay fluctuations, a large-dynamic-range time pre-compensator with high precision is implemented at the local site, enabling a time signal at the remote site is accurately synchronized with the clock at the local site. Our experiments demonstrate that stabilities in terms of time deviation (TDEV) of less than 29.8 ps at 1s and 5.2 ps at 10 4 s and the clock difference of less than 28 ps can be achieved for the fiber link up to 200 km.

Highlights

High precision fiber-optic time synchronization has attracted extensive research interest over the last two decades in the applications of metrology, telecommunication, navigation and atomic timescales development, where time deviation with the order of pico-second are required, because of fiber-optic’s unique advantages of broad bandwidth, low attenuation, and immunity to electromagnetic interference, etc [1]–[3]
We propose a fiber-optic time synchronization scheme based on the bidirectional wavelength division multiplexing (WDM) transmission without requiring any complex optical-fiber link calibrations
The time difference between the local 1PPS and the received one at the local site is measured by a time interval counter (TIC), which is used to control the time delay adjuster (TDA) to pre-compensate the propagation delay fluctuations introduced by the optical fiber

Summary

Introduction

High precision fiber-optic time synchronization has attracted extensive research interest over the last two decades in the applications of metrology, telecommunication, navigation and atomic timescales development, where time deviation with the order of pico-second are required, because of fiber-optic’s unique advantages of broad bandwidth, low attenuation, and immunity to electromagnetic interference, etc [1]–[3]. We propose a fiber-optic time synchronization scheme based on the bidirectional wavelength division multiplexing (WDM) transmission without requiring any complex optical-fiber link calibrations.

Results

Conclusion