Distributed high-precision time transfer through passive optical networks

We propose a one-point to multipoint distributed time transfer through passive optical networks using a time division multiple access (TDMA) based two-way time transfer. The clock at each clock user node is, in turn, compared with the high-precision reference clock at a master node by a two-way time transfer during assigned subperiods. The corresponding TDMA control protocol and time transfer units for the proposed scheme are designed and implemented. A 1 x 8 experimental system with a 20 km single-mode fiber in each subpath is demonstrated. The results show that a standard deviation of < 60 ps can be reached in each comparison subperiod. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)