Fig. 1. Time synchronization system based on BTDM-SFSW

Fig. 2. Time sequence diagram of the BTDM-SFSW system

Fig. 3. Structure of the PID controller

Fig. 4. Result of time synchronization. (a) Clock difference after synchronization; (b) TDEV of the clock difference

Fig. 5. Clock differences after time synchronization of different length optical fibers

Fig. 6. Result of time synchronization over 60 km field fiber link. (a) Time difference after synchronization; (b) TDEV of the time difference