FEL2013 - List of Authors (Chen, L.)

Paper	Title	Page
WEPSO33	Remote RF Synchronization With Femtosecond Drift at PAL	570
	J. Kim, K. Jung, J. Lim KAIST, Daejeon, Republic of Korea L. Chen Idesta Quantum Electronics, New Jersey, USA S. Hunziker PSI, Villigen PSI, Switzerland F.X. Kaertner CFEL, Hamburg, Germany H.-S. Kang, C.-K. Min PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: This research was supported by the PAL-XFEL Project, South Korea. We present our recent progress in remote RF synchronization using an optical way at PAL. A 79.33-MHz, low-jitter fiber laser is used as an optical master oscillator (OMO), which is locked to the 2.856-GHz RF master oscillator (RMO) using a balanced optical-microwave phase detector (BOM-PD). The locked optical pulse train is then transferred via a timing-stabilized 610-m long optical fiber link. The output is locked to the 2.856 GHz voltage controlled oscillator (VCO) using the second BOM-PD, which results in remote synchronization between the RMO and the VCO. We measured the long-term phase drift between the input optical pulse train and the remote RF signals using an out-of-loop BOM-PD, which results in 2.7 fs (rms) drift maintained over 7 hours. We are currently working to measure the phase drift between the two RF signals and reduce the phase drift over longer measurement time.

WEPSO37	Femtosecond Fiber Timing Distribution System for the Linac Coherent Light Source	583
	H. Li, P.H. Bucksbaum, J.C. Frisch, A.R. Fry, J. May, K. Muehlig, S.R. Smith SLAC, Menlo Park, California, USA L. Chen, H.P.H. Cheng Idesta Quantum Electronics, New Jersey, USA F.X. Kaertner CFEL, Hamburg, Germany F.X. Kaertner MIT, Cambridge, Massachusetts, USA A. Uttamadoss PU, Princeton, New Jersey, USA
	Funding: This work is supported by Department of Energy under STTR grant DE-C0004702. We present the design and progress of a femtosecond fiber timing distribution system for the Linac Coherent Light Source (LCLS) at SLAC to enable the machine diagnostic at the 10 fs level. The LCLS at the SLAC is the world’s first hard x-ray free-electron laser (FEL) with unprecedented peak brightness and pulse duration. The time-resolved optical/x-ray pump-probe experiments on this facility open the era of exploring the ultrafast dynamics of atoms, molecules, proteins, and condensed matter. However, the temporal resolution of current experiments is limited by the time jitter between the optical and x-ray pulses. Recently, sub-25 fs rms jitter is achieved from an x-ray/optical cross-correlator at the LCLS, and external seeding is expected to reduce the intrinsic timing jitter, which would enable full synchronization of the optical and x-ray pulses with sub-10 fs precision. Of such a technique, synchronization between seed and pump lasers would be implemented. Preliminary test results of the major components for a 4 link system will be presented. Currently, the system is geared towards diagnostics to study the various sources of jitter at the LCLS. P. Emma et al.,Nat. Photonics 4,641-647(2010). J. Kim et al.,Opt. Lett,, 31,3659(2006). J. Kim et al.,Opt. Lett,, 32,1044(2007). J.Kim et al.,Nat. Photonics 2,733-736(2008).

Paper

Title

Page

Remote RF Synchronization With Femtosecond Drift at PAL

570

J. Kim, K. Jung, J. Lim
KAIST, Daejeon, Republic of Korea
L. Chen
Idesta Quantum Electronics, New Jersey, USA
S. Hunziker
PSI, Villigen PSI, Switzerland
F.X. Kaertner
CFEL, Hamburg, Germany
H.-S. Kang, C.-K. Min
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This research was supported by the PAL-XFEL Project, South Korea.
We present our recent progress in remote RF synchronization using an optical way at PAL. A 79.33-MHz, low-jitter fiber laser is used as an optical master oscillator (OMO), which is locked to the 2.856-GHz RF master oscillator (RMO) using a balanced optical-microwave phase detector (BOM-PD). The locked optical pulse train is then transferred via a timing-stabilized 610-m long optical fiber link. The output is locked to the 2.856 GHz voltage controlled oscillator (VCO) using the second BOM-PD, which results in remote synchronization between the RMO and the VCO. We measured the long-term phase drift between the input optical pulse train and the remote RF signals using an out-of-loop BOM-PD, which results in 2.7 fs (rms) drift maintained over 7 hours. We are currently working to measure the phase drift between the two RF signals and reduce the phase drift over longer measurement time.

WEPSO37

Femtosecond Fiber Timing Distribution System for the Linac Coherent Light Source

583

H. Li, P.H. Bucksbaum, J.C. Frisch, A.R. Fry, J. May, K. Muehlig, S.R. Smith
SLAC, Menlo Park, California, USA
L. Chen, H.P.H. Cheng
Idesta Quantum Electronics, New Jersey, USA
F.X. Kaertner
CFEL, Hamburg, Germany
F.X. Kaertner
MIT, Cambridge, Massachusetts, USA
A. Uttamadoss
PU, Princeton, New Jersey, USA

Funding: This work is supported by Department of Energy under STTR grant DE-C0004702.
We present the design and progress of a femtosecond fiber timing distribution system for the Linac Coherent Light Source (LCLS) at SLAC to enable the machine diagnostic at the 10 fs level. The LCLS at the SLAC is the world’s first hard x-ray free-electron laser (FEL) with unprecedented peak brightness and pulse duration. The time-resolved optical/x-ray pump-probe experiments on this facility open the era of exploring the ultrafast dynamics of atoms, molecules, proteins, and condensed matter. However, the temporal resolution of current experiments is limited by the time jitter between the optical and x-ray pulses. Recently, sub-25 fs rms jitter is achieved from an x-ray/optical cross-correlator at the LCLS, and external seeding is expected to reduce the intrinsic timing jitter, which would enable full synchronization of the optical and x-ray pulses with sub-10 fs precision. Of such a technique, synchronization between seed and pump lasers would be implemented. Preliminary test results of the major components for a 4 link system will be presented. Currently, the system is geared towards diagnostics to study the various sources of jitter at the LCLS.
*P. Emma et al.,Nat. Photonics 4,641-647(2010).
*J. Kim et al.,Opt. Lett,, 31,3659(2006).
*J. Kim et al.,Opt. Lett,, 32,1044(2007).
*J.Kim et al.,Nat. Photonics 2,733-736(2008).