Research On High Stability Time & Frequency Signal Optical Fiber Transmission And Restoration

Satellite navigation and deep space exploration need high performance time and frequency source.High precision time and frequency signal transmission or synchronization is also one of the key technologies.The high stable frequency source and the high precision time and frequency transfer technology have very important scientific value.High stability,low phase noise hydrogen atom clock signal is often employed as the local frequency source for satellite navigation and deep space exploration control system.For time and frequency signal system distribution in different areas,hydrogen maser frequency signal needs to be accurately transmitted to each user port.When using a long distance coaxial cable to transmit high stable frequency signal,power loss is large.This paper study the optical fiber transmission technologies of high stability time and frequency signal.When we transmit frequency signal over a long optical fiber,its phase noise and stability quality will be degraded.Remote satellite navigation measurement and control system need the frequency reference sources with the same quality as that at the optical fiber sender.Signal remote transmission through the optical fiber will induce a fixed time delay.Environmental factors such as temperature fluctuations will also affect the signal phase of time.Remote optical receivers and optical fiber senders realize time synchronization.This paper study the frequency purification technology,time and frequency signal phase synchronization recovery technology.We have carried out the time frequency signal fiber transmission and restoration experiment to verify the proposed technique.The results show that the phase noise and frequency stability of the restoration 10 MHz after optical fiber transmission can reach-118.1 dBc/Hz@1Hz and 3 10^-13@1s.After optical fiber time transmission and restoration,there is almost no time delay between the time at the transmitting end and the one at the receiving end.The RMS of the long-term time fluctuation is less than150ps between center and remote terminals.