Since an 80 km experiment conducted by Tsinghua University in 2011 achieved a frequency stability of 7×10⁻¹⁵/s and a synchronization precision of 50 ps, fiber-optic time-frequency synchronization technology has been progressively applied to projects such as Very Long Baseline Interferometry (VLBI) and the Square Kilometre Array (SKA).
The SKA project requires time synchronization to achieve a short-term precision of 1 ps and a long-term stability of 10 ns over a 10-year period.