Simultaneous Frequency Transfer and Time Synchronization over a Cascaded Fiber Link of 230 km
刘琴 Liu Qin, 陈炜 Chen Wei, Xu Dan, 程楠 Cheng Nan, 杨飞 Yang Fei, 桂有珍 Gui Youzhen, 蔡海文 Cai Haiwen, 韩申生 Han Shensheng · Chinese Journal of Lasers · 2016
The joint transfer of frequency and one pulse-per-second time signals based on dense wavelength division multiplexing technology is demonstrated over a compensated cascaded fiber link of 230 km, consisting of two stages of fiber links with lengths of 150 km and 80 k m. A bi-directional erbium-doped fiber amplifier is inserted in the center of 150 km fiber link to compensate for significant optical attenuation. After every stage has achieved the steady state by optical compensation, the Allan deviation of frequency signal of the cascaded system is 3.1*10~(-14) at 1 s and 6.3 * 10~(-18) at 10~4s respectively; the time deviation of time signal is less than 3.5 ps at an averaging time of 10~2 s to 10~4 s. Further, it is verified that the stability of the cascaded link is the standard deviation of the stabilities of the two stages links for both frequency and time signals. After calibration, time synchronization is also realized and the accuracy is within 90 ps.