University of Ljubljana, Faculty of Electrical Engineering, Ljubljana
I-Tech, Solkan
ELETTRA, Basovizza
This paper presents a good solution for timing distribution and RF synchronization of multiple events at multiple remote locations in the accelerator facility with femtosecond precision. The proposed electro-optical synchronization system makes use of commercial telecom single-mode optical fibre operating at 1550 nm. Such fibre is subject to change in phase and group velocity correlated to temperature variations and is sensitive to acoustic perturbations. The synchronization system described makes use of stabilization of the fibre link which transports low-jitter microwave signal over a distance of 300 m. It consists of a transmitter, located at the place of low-jitter master oscillator, and receiver, located at the remote location. Both units are connected by a pair of optical single-mode fibres. Using a fibre pair instead of a single fibre allows for compensation of fibre-length changes. The added timing jitter of 20 fs at 100 Hz - 20 MHz is measured on the first experimental synchronization system. Even lower jitter is expected by some planned improvements in the transfer system and the industrialization of it.
