Counting and metrology of distributed atomic clocks using metropolitan fiber

We demonstrate a distributed atomic clocks network between Shanghai Instituteof Optics and fine Mechanics (SIOM) and Shanghai Institute of Measurement andTest (SIMT). The frequency signals from three different clocks transfer in onefiber link and four clocks can have comparison in two different labs.Bycomparing the results of the comparison between the two labs, it was found thatthe consistency of the frequency signal is on the order of lower than 1E-15.And we also achieve consistency between two locations at the E-15 level offrequency reporting. This scheme can achieve distributed time counting andfrequency dissemination of remote atomic clocks, which is a new exploration ofthe future time keeping laboratory mode.