Research On The Method Of Frequency Transfer And Remote Time Frequency Traceability Based On Optical Fiber

With the development of society and the advancement of science and technology,the demand for time-frequency in various trades has been improving.How to transmit stringent specification time-frequency signals with high precision and stability has attracted the attention of researchers.Based on the vigorous development of optical fiber technology in recent years,optical fiber technology has been paid attention to and developed in the field of time-frequency.Optical fiber can transmit time-frequency signals with high precision and high stability.In this paper,we have studied the development and application of fiber in time-frequency transmission according to three parts.The first part is the one-way optical fiber frequency transmission,which will transmit the 5 MHz or 10 MHz frequency signals generated by the atomic clock with low-cost high-stability transmitted and the performance of the frequency transmit system was evaluated.The second part is the two way optical time-frequency and transport.The real-time comparison software is developed for two way optical time-frequency and transport based on the current status of two way optical time-frequency and transport.The third part is the remote time frequency traceability of optical fiber.Based on the two way optical time-frequency and transport,the local time source is traced to the national highest reference time with high-precision.This paper is mainly elaborated in the following four parts:First,the related knowledge background of time-frequency and time-frequency transmission is introduced,and the application of fiber in the field of time-frequency is introduced.According to the research status of optical fiber in the field of time-frequency,the current problems and deficiencies are proposed,and the research focus and preliminary experiment effect are proposed.Second,due to the high cost and low transmission stability of the current one-way optical fiber frequency transmission technology,this paper designs and realizes the one-way optical fiber frequency transmit the national highest reference UTC(NIM)frequency signal through the 100km fiber based on lower cost.And the frequency stability is 2.07x10-13/s and 1.7x10-13/d after transmitted.At the same time,the interference of equipment,optical fiber distance and temperature to the frequency in the one-way optical fiber frequency transmission system is measured and evaluated.Thirdly,according to the current status of two way optical time-frequency and transport of the National Institute of Metrology(NIM)in China,the two way real-time comparison software is developed.Real-time comparison software realizes real-time processing and visualization of data of two way optical time-frequency and transport,and also increases the monitoring of the operation of two way optical time-frequency and transport system.The performance of the real-time comparison software is verified by comparing the processed data with the original data.By comparing the data processed by the real-time comparison software with the results of GNSS(Global Navigation Site System)common view comparison result under the common clock,it is verified that the two way optical time-frequency and transport has accurate and stable transmission performance.Fourth,based on the advantages of high precision and high stability of two way optical time-frequency and transport,the remote time traceability of fiber is designed and realized.The result of two way optical frequency and time transport is tamed through PID taming algorithm,and finally the traceability effect of time difference fluctuation within 1.5 ns and frequency stability 1 x 10-17 is obtained.