Individual experimental stations are spread over long distances in extensive facilities such as synchrotrons or particle accelerators. Sometimes they are hundreds of meters or even kilometers apart and still require high temporal synchronization on a femtosecond level.
To run such a system, a central radio frequency (RF) is typically provided via a master clock and used to synchronize all clients precisely. For this, the timing signal has to be distributed with high accuracy.
One obvious approach for such a timing distribution system would be to deliver the electric signal directly to the clients. However, this way the signal is quite susceptible to disturbances such as temperature, humidity, etc. So, how can the signal be transferred, avoiding such environmental influences?
For this task, many large scientific facilities worldwide rely on Cycle’s PULSE or WAVE timing systems. Their basic idea is to transform the RF signal into an optical signal which is much more stable than the electromagnetic signal when distributed over long distances. The facility’s RF signal is imprinted onto a laser, and then the laser signal is coupled to timing-stabilized polarization-maintaining (PM) optical fiber links that distribute the signal to the remote clients. The optical fiber network comprises a feedback system to compensate fluctuations upon signal transmission. At the client sites, the timing signal is used to synchronize either a remote laser via a BOC or to a microwave source (voltage controlled oscillator) via a BOMPD, respectively.