FEL2011 - List of Authors (Gessler, P.)

Paper	Title	Page
WEPA19	Report on the Redesign of the Fibre Link Stabilisation Units at FLASH	370
	M.K. Bock, M. Bousonville, M. Felber, P. Gessler, T. Lamb, H. Schlarb, B. Schmidt, S. Schulz DESY, Hamburg, Germany M. Kuntzsch HZDR, Dresden, Germany
	Funding: This work is partly supported by IRUVX-PP an EU co-funded project under FP7 (Grant Agreement 211285) Recently, the fibre link stabilisation unit of the optical synchronisation system at FLASH has been subject to several design changes involving some major issues. Enhancements of the optical design have led to improvements in the efficiency of the free space optics and a new optical delay line allows for a more than two times longer adjustment range. The amplitude noise, encountered previously at the remote station of the links, was drastically decreased by a new beam splitting configuration. In future, this new link design will not only be used for the planned additional fibre links at FLASH, but it will also replace the already installed ones. In this paper we report on the changes of opto-mechanical design and we present first results from the recently commissioned links.

THPA14	Upgrade of the Optical Synchronization System for FLASH II	496
	M. Felber, M.K. Bock, M. Bousonville, P. Gessler, T. Lamb, S. Ruzin, H. Schlarb, B. Schmidt, S. Schulz DESY, Hamburg, Germany
	The optical synchronization system at FLASH has been in operation since 2008. Due to continuous improvement and several upgrades it has become an integral part of the machine operation and of pump-probe experiments as both rely on its performance. In summer 2013, a second FEL section, called FLASH II, which is using the same accelerator as FLASH will start its operation to increase the number of user experiments and to test new seeding schemes. This also requires a major extension of the synchronization system since new clients have to be supplied with a 10 fs-stable timing signal. Six additional stabilized fiber links and the according end stations like bunch arrival time monitors and laser synchronization setups will be installed.

THPA32	Femtosecond Stable Laser-to-RF Phase Detection Using Optical Modulators	551
	T. Lamb, M.K. Bock, M. Bousonville, M. Felber, P. Gessler, F. Ludwig, S. Ruzin, H. Schlarb, B. Schmidt, S. Schulz DESY, Hamburg, Germany E. Janas Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	Free-Electron Lasers like FLASH and the European XFEL require the synchronization of RF stations to the optical timing reference of the accelerator. For this purpose, a new technique to phase-lock RF sources to an optical pulse train has been invented. The new technique uses an opto-microwave coupling device together with an ultra-low phase-noise RF source operating at a frequency of 1.3 GHz. In our arrangement, the laser-to-RF phase detector is insensitive to amplitude fluctuations of the optical reference pulse train, which allows the detector to achieve femtosecond precision over long time periods. In this paper, we present the balanced laser-to-RF phase detection principle along with a tolerance study of the arrangement and first results from our prototype setup.

Paper

Title

Page

Report on the Redesign of the Fibre Link Stabilisation Units at FLASH

370

M.K. Bock, M. Bousonville, M. Felber, P. Gessler, T. Lamb, H. Schlarb, B. Schmidt, S. Schulz
DESY, Hamburg, Germany
M. Kuntzsch
HZDR, Dresden, Germany

Funding: This work is partly supported by IRUVX-PP an EU co-funded project under FP7 (Grant Agreement 211285)
Recently, the fibre link stabilisation unit of the optical synchronisation system at FLASH has been subject to several design changes involving some major issues. Enhancements of the optical design have led to improvements in the efficiency of the free space optics and a new optical delay line allows for a more than two times longer adjustment range. The amplitude noise, encountered previously at the remote station of the links, was drastically decreased by a new beam splitting configuration. In future, this new link design will not only be used for the planned additional fibre links at FLASH, but it will also replace the already installed ones. In this paper we report on the changes of opto-mechanical design and we present first results from the recently commissioned links.

THPA14

Upgrade of the Optical Synchronization System for FLASH II

496

M. Felber, M.K. Bock, M. Bousonville, P. Gessler, T. Lamb, S. Ruzin, H. Schlarb, B. Schmidt, S. Schulz
DESY, Hamburg, Germany

The optical synchronization system at FLASH has been in operation since 2008. Due to continuous improvement and several upgrades it has become an integral part of the machine operation and of pump-probe experiments as both rely on its performance. In summer 2013, a second FEL section, called FLASH II, which is using the same accelerator as FLASH will start its operation to increase the number of user experiments and to test new seeding schemes. This also requires a major extension of the synchronization system since new clients have to be supplied with a 10 fs-stable timing signal. Six additional stabilized fiber links and the according end stations like bunch arrival time monitors and laser synchronization setups will be installed.

THPA32

Femtosecond Stable Laser-to-RF Phase Detection Using Optical Modulators

551

T. Lamb, M.K. Bock, M. Bousonville, M. Felber, P. Gessler, F. Ludwig, S. Ruzin, H. Schlarb, B. Schmidt, S. Schulz
DESY, Hamburg, Germany
E. Janas
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

Free-Electron Lasers like FLASH and the European XFEL require the synchronization of RF stations to the optical timing reference of the accelerator. For this purpose, a new technique to phase-lock RF sources to an optical pulse train has been invented. The new technique uses an opto-microwave coupling device together with an ultra-low phase-noise RF source operating at a frequency of 1.3 GHz. In our arrangement, the laser-to-RF phase detector is insensitive to amplitude fluctuations of the optical reference pulse train, which allows the detector to achieve femtosecond precision over long time periods. In this paper, we present the balanced laser-to-RF phase detection principle along with a tolerance study of the arrangement and first results from our prototype setup.