Synchronization of Clocks in the 100 Ps Range

摘要

The development of a method for measuring, with high resolution (100 ps), the differences between distant atomic clocks is presented. The synchronization operation is analyzed and the main characteristics of the set of measuring units are determined. The principle of the system is described as the transfer of the time information by an optical channel using a semiconductor laser. The various instruments including time scalas, transducers, telescopes, and chronometers are described. The results of two experiments concerning the synchronization of clocks from 6 km apart to several thousand km apart are presented. The synchronization method by laser beam achieves the expected accuracy of 100 ps when the clocks are in direct view and is better than 1 ps when they are separated by several hundred kilometers.