Experimental demonstration of non-reciprocity effects on satellite-based two-way time-frequency transfer links

• ting zeng, Qi Shen, Yuan Cao, Jian-Yu Guan, Meng-Zhe Lian, Jin-Jian Han, lei hou, jian lu, xinxin peng, Min Li, WeiYue Liu, Jincai Wu, yong wang, Juan Yin, Ji-Gang Ren, Hai-Feng Jiang, Qiang Zhang, Cheng-Zhi Peng, and Jian-Wei Pan
• received 11/06/2023; accepted 04/02/2024; posted 04/02/2024; Doc. ID 511141
• Abstract: Future optical clock networks will require high-precision optical time-frequency transfer between satellites and ground stations. However, the standard two-way time transfer's time-of-flight reciprocity breaks down due to the spatio-temporal displacement caused by point-ahead effects and delay effects between the satellite and ground. Here, we experimentally demonstrate the impact of spatio-temporal displacement on high-precision optical time-frequency transfer between two stationary terminals located 113 km apart. We implement optical transceiver in each terminal with separate transmitting and receiving paths using an orthogonal polarization scheme, and construct a separate two-way atmospheric link with an asymmetric distance of 174 mm which is a consequence of point-ahead effects. Additionally, the delay effect is simulated by shifting the time labels of one side with the experimental data. Our experiment show that the impact of spatio-temporal displacement on the link instability is less than 2.3 ×10^{-19} at 10000 s. This indicates that when the link instability of satellite-ground optical time-frequency transfer is on the order of 10^{-19}, it is not necessary to consider non-reciprocal point-ahead effects and delay effects.