Accurate and fast fiber transfer delay measurement based on phase   discrimination and frequency measurement
  An accurate and fast fiber transfer delay measurement method is demonstrated. As a key technique, a simple ambiguity resolving process based on phase discrimination and frequency measurement is used to overcome the contradiction between measurement accuracy and system complexity. The optimized system achieves a high accuracy of 0.3 ps with a 0.1 ps resolution, and a large dynamic range up to 50 km as well as no dead zone. 
J. W. Dong, B. Wang, C. Gao, and L. J. Wang
physics.ins-det physics.optics