利用西安和咸阳之间的电信省级骨干光纤网构建了210 km的光学频率信号传递测试链路，链路损耗为0.23 dB/km。实验中采用可搬运、基于光纤干涉仪、线宽约为200 Hz的激光器作为光源，利用两台低噪声双向掺铒光纤放大器(EDFA)补偿光纤链路损耗和增加光信号的传输距离，放大器平均增益控制在15 dB左右，以防止激射。通过测量和分析不同情况下光纤链路的附加相位噪声，可观测到铁路震动引起的规律性干扰。当噪声抑制系统在锁定状态时，链路的相位噪声被抑制了23 dB，在剔除铁路干扰时段数据后，获得的210 km实地通信链路的秒级频率稳定度达到了1.51×10-14，万秒频率稳定度达到了5×10-17。利用210 km通信链路进行了光学频率信号的远程传递测试，分析了限制频率稳定度的主要影响因素，并针对现行光纤布设方式提出了补充要求。该研究为基于通信链路的高精度光学频率信号的传递与比对提供理论支撑。

We establish a 210 km optical frequency signal transfer test link along the telecom provincial backbone optical fiber network between Xi’an and Xian Yang, and the loss of the link is 0.23 dB/km. A fiber interferometer based laser with linewidth of 200 Hz is used as the light source, and the laser is conveyable. Two bilateral erbium-doped optical fiber amplifiers (EDFAs) with low noise are used to compensate the fiber link loss and increase the transmission distance of signal. The average gain of amplifier is controlled at about 15 dB to avoid the self-excited oscillation. The additional phase noise of the fiber link under different conditions is measured and analyzed, and the regular disturbance caused by the railway vibration is observed. The phase noise in the link is suppressed by 23 dB when we use the noise suppression system. When the noise data from the railway vibration is eliminated, the second level frequency stability of the 210 km urban communication link can achieve 1.51×10-14 and be better than 5×10-17 at 104 s. The remote transfer test for optical frequency signal based on 210 km communication link is completed, and the main influence factors limiting the frequency stability are analyzed. The supplementary requirements are put forward for the current fiber setting way. The study provides theoretical supplement for achieving high accuracy optical frequency signal transmission and comparison based on the communication link.