1 中国科学院上海光学精密机械研究所中科院量子光学重点实验室, 上海 201800
2 中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室, 上海 201800
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 km . 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 104 s respectively; the time deviation of time signal is less than 3.5 ps at an averaging time of 102 s to 104 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.