Hunziker, S. Arsov, V.R. Buechi, F. Dach, M. Heiniger, M. Kaiser, M.G. Kramert, R. Romann, A. Schlott, V. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-TUPCC17 English 189-192 TUPCC17 ion FEL detector timing controls Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-TUPCC17 http://jacow.org/ibic2017/papers/tupcc17.pdf The reference distribution for the SwissFEL accelerator is based on ultra-stable Libera Sync 3 fiber-optic links operating at 3 GHz with <2.4fs added timing jitter. While s-band injector RF stations are directly supplied with these actively stabilized reference signals at 2.9988GHz, the same 3 GHz optical links are used to transmit reference signals at 2.856GHz (half c-band frequency) to the c-band LINACs, combined with a frequency doubler-amplifier at the link end. A novel zero AM/PM-conversion frequency-doubler and an amplitude-/phase-controlled power amplifier have been implemented in a compact 1HU 19inch unit. Key design concepts and measurement results will be presented. It will be shown that this inexpensive doubler-amplifier system adds only insignificant jitter and drift to the transmitted reference signals. As the same actively stabilized 3GHz links can be used for s- and c- band RF stations, development of a more expensive 6GHz fiber-optic link could be avoided. A higher quantity of the same link type can thus be manufactured and the number of spares is reduced as only one link type is utilized for the SwissFEL injector and LINAC RF reference signals.