Master Oscillator Design for the VUV-FEL Project

The VUV-FEL [1] is a free electron laser facility being commissioned at DESY [2] Hamburg. It includes seven RF stations distributed over a distance of 300 meters. Multiple RF devices at each station operating at frequencies in the range of 1 MHz to 2.8 GHz must be synchronized with sub picosecond accuracy. To fulfil the short and long term synchronization requirements a phase reference distribution system has been developed. It consists of a master oscillator (MO), signal distribution system and a fiber-optic phase monitoring link [3]. This paper describes the most important design issues of the MO. Phase noise and phase drift are addressed and the appropriate solutions used for minimizing those sources of errors are presented. Current status of the MO is described with measurement confirming the required performance.