High Precision Time and Frequency Transfer on 275 km Beijing-Shanghai Fiber Backbone

To achieve high precision timing and punctuality in quasi national territory,time and frequency signal of high precision atomic clocks,such as cesium clock or hydrogen maser,is transferred by using fiber to examine the transfer performance of long distance on actual fiber link.By adopting the methods of wavelength division multiplexing and dual wavelength bi-directional transmitting,the related work of achieving high precision time and frequency signal is introduced on 275 km Beijing-Shanghai backbone.Based on the characteristics of long distance fiber link,the impact of loss and scattering of link,dispersion and frequency noise,feedback loop bandwidth and dynamic range of compensating system on time and frequency transfer performance is discussed.Results show that the frequency stabilities are up to 5*10-14 in one second averaging time and 7*10-14 in one day averaging time,and time synchronization stabilities are up to 2.4ps in one thousand second averaging time.