Pulsed optical timing distribution system with sub-ps accuracy for applications in geodesy.

Kurzfassung

Here we report on the recent progress of the highly stable optical pulsed Timing Distribution System (TDS) commissioned at the geodetic observatory in Wettzell (Germany). The system connects a master clock (H-maser) to a mode-locked femtosecond-laser, which in turn uses delay compensated fiber lines for the coherent transmission of time and frequency. In order to use time itself for sensitive delay compensation, we developed a new generation of electronic interfaces for the generation and distribution of Pulse-Per-Second (PPS) signals with sub-ps stability, a low temperature coefficient (1ps/°C) and a constant delay with respect to the master reference. For the interfacing to the respective measurement systems, a set of required standard RF-Signals (5, 10, 100 MHz) with low phase noise (-160 dBc/Hz at 10kHz) and high fractional frequency stability (Allan Deviation 8x10-14 in 1s) are provided. This indicates that the system indeed distributes the stability of the master clock without penalties, which is equivalent to having a true copy of the master clock in perfect synchronization at each end point.