overview of laser, timing, and synchronization issues
DESCRIPTION
Overview of laser, timing, and synchronization issues John Corlett , Larry Doolittle, Bill Fawley, Steven Lidia, Bob Schoenlein, John Staples, Russell Wilcox, Sasha Zholents LBNL. Scientific goal - application of ultrafast x-ray sources to study dynamics with high-resolution. x-ray probe. - PowerPoint PPT PresentationTRANSCRIPT
John Corlett, July 2004
Overview of laser, timing, and
synchronization issues
John Corlett, Larry Doolittle, Bill Fawley, Steven Lidia, Bob Schoenlein, John Staples, Russell
Wilcox, Sasha Zholents
LBNL
John Corlett, July 2004
• Diffraction and spectroscopy • Nuclear positions and electronic, chemical or structural
probes
Scientific goal - application of ultrafast x-ray sources to study dynamics with high-
resolution
diffraction angle
time delay
time delay
x-ray probe
visible pump
detector
Time-resolved x-ray diffraction
Time-resolved EXAFS
NEXAFSdelay
x-ray probe
visible pump
r
energy
time
Kedge
abso
rptio
n
f(r)
Plus photoelectron spectroscopy, photoemission microscopy, etc
• Access new science in the time-domain x-ray regime
John Corlett, July 2004
• Ultrafast laser pulse “pumps” a process in the sample• Ultrafast x-ray pulse “probes” the sample after time ∆t
• Ultrafast lasers an integral part of the process• X-rays produced by radiation in an electron accelerator
Pump-probe experiment concept
Laser excitation pulse
X-ray probe pulse
∆t
ion or e- detector
-detector
sample
John Corlett, July 2004
• Both laser and x-ray pulses should be stable in temporal and spatial distributions
• Parameters and quality of x-ray pulse determined by the electron beam
• Accelerator parameters • Synchronization between laser and x-ray pulses, ∆t, should ideally
be known and controllable - to the level of the pulse duration itself ~ 10 fs
Pump-probe experiment concept
Laser excitation pulse
X-ray probe pulse
∆t
ion or e- detector
-detector
sample
John Corlett, July 2004
Many projects around the world are addressing the need for ultrafast x-rays, in different ways
• LCLS: linac SASE (construction)• BNL DUV FEL: linac HGHG (operational)• DESY TTF-II: linac SASE (construction)• SPPS: linac spontaneous emission from short bunches
(operational)
• ALFF: linac SASE • BESSY FEL: linac HGHG• European X-ray FEL: linac SASE• Daresbury 4GLS: ERL HGHG + spontaneous• LUX: recirculating linac HGHG + spontaneous• Cornell ERL: ERL spontaneous• MIT-Bates X-ray FEL: linac HGHG + SASE• Arc-en-Ciel: recirculating linac / ERL HGHG + SASE• FERMI@Elettra: linac HGHG• BNL PERL: ERL spontaneous
John Corlett, July 2004
What are the difficulties in achieving x-ray beam quality?
• X-rays are produced by electrons emitting synchrotron radiation in an accelerator
• The electron beams are manipulated by rf and magnetic systems• The x-ray beam quality is limited by the electron beam quality in
many ways– Electron bunch charge, energy, emittance, energy spread, bunch
length, position, … • At the radiator!
• Production of high-brightness bunches is tough enough– Emission process, space charge, rf focusing, ….
• Then we must accelerate and otherwise manipulate the bunches before they reach the radiating insertion device
• Many opportunities to degrade the electron bunch– Space charge, rf focussing, emittance compensation, CSR, geometric
wakefields, rf field curvature, resistive wall wakefields, optics aberrations, optics errors, alignment, rf phase errors, rf amplitude errors, …
John Corlett, July 2004
Synchronization
• In addition to the electron bunch properties, the need for synchronization of the x-ray pulse to a reference signal - the pump - is required for many experiments– Time between pump signal and probe x-ray pulse
• Predictable or measurable• Stable to ~ pump & probe pulse durations
• This presents additional demands on the accelerator, instrumentation, and diagnostics systems
• Various techniques may be employed to enhance synchronization– Slit spoiler for SASE – Seeding
• HGHG• ESASE (Enhanced SASE)
– e- bunch manipulation & x-ray compression– Measurement of relative x-ray - pump laser timing
• Electro-optic sampling of electron bunch fields• Time-resolved detection of x-ray and laser pulses at the sample
John Corlett, July 2004
The roles of lasers, timing,and synchronization in an ultrafast x-ray
facility• Laser systems
– Generate the high-brightness electron beam in an rf photocathode gun– Produce the pump signals at the beamline endstations
• Timing system– Provides reference signals to trigger (pulsed) accelerator systems – Provides reference waveforms to synchronize rf systems– Provides reference waveforms to synchronize endstation lasers
• Synchronization– To control and determine the timing of the x-ray pulse with respect to
a pump pulse – Requires stable systems in the x-ray facility, connected by a “stable”
timing system including stable timing distribution systems• The timing system only has to be “stable” enough for all of the components
connected to it to follow it’s timing jitter (to the required level)• Phase noise ˛ timing jitter
• The majority of the timing jitter must be within the bandwidth of the accelerator & laser systems such that they can follow
– Local feedback around rf & laser systems– Lock to timing system master oscillator
0
f
f
rms f2
df)f(L2t
2
1
π=Δ
∫
John Corlett, July 2004
0
f
f
rms f2
df)f(L2t
2
1
π=Δ
∫
Phase noise and timing jitter
John Corlett, July 2004
Some space and time parameters for a conceptual ultrafast x-ray facility
rf photocathode gun Linac Undulators
Bend magnets / compressor
End stations
• 10 fs ≈ 3 µm at c• Thermal expansion for ∆T = 0.1°C in Cu over 100 m
≈ 170 µm or 570 fs• Similar magnitude effect from refractive index change in optical fiber
Length scale ~ 100’s mTime scale ~ µsEquivalent bandwidth ~ 100’s kHz
John Corlett, July 2004
Some rf systems parameters for a conceptual ultrafast x-ray facility
rf photocathode gun Linac Undulators
Bend magnets / compressor
End stations
• 10 fs ≈ 5x10-3 °rf phase L-band• Cavity filling time (Q=104) ≈ 2 µs
• Bandwidth ~ 100 kHz• Cavity filling time (Q=107) ≈ 2 ms
• Bandwidth ~ 100 Hz • 10 fs ≈ 1x10-2 °rf phase S-band• Cavity filling time (Q=104) ≈ 1 µs
• Bandwidth ~ 300 kHz
John Corlett, July 2004
Synchronize rf systems to a master oscillator
• Control phase and amplitude of the rf fields experienced by the electron beam
• The master oscillator must have a phase noise spectrum such that the majority of the timing jitter is accumulated within the bandwidth of the rf systems
• Local feedback ensures that the rf systems follow jitter in the master oscillator
• Noise sources• Microphonics• Thermal drift• Electronic noise• Digital word
length
John Corlett, July 2004
Choice of master oscillator
• rf crystal oscillator has low noise close to carrier• Laser has low noise above ~ 1 kHz
• Mode locked laser locked to good crystal oscillator provides a suitable master oscillator • Active mode-lock cannot respond rapidly to perturbations
John Corlett, July 2004
Although there are very good low-noise sapphire loaded cavity oscillators
http://www.psi.com.au/pdfs/PSI_SLCO.pdf
John Corlett, July 2004
Phase noise spectrum requirement
• Master oscillator phase noise within bandwidth of feedback systems can be corrected
• Residual uncontrolled phase noise plus noise outside feedback systems bandwidth results in timing jitter and synchronization limit
John Corlett, July 2004
Laser synchronization
• two independent psec Mira 900-P (Coherent) lasers• PLLs at 80 MHz (n=1) and 14 GHz (n=175)
D.J. Jones et al., Rev. Sci. Instruments, 73, 2843 (2002).
time (sec)
• Sub-femtosecond timing jitter has been demonstrated between two mode-locked Ti:sapphire lasers• Limit is electronic noise (under favorable conditions)
John Corlett, July 2004
Sophisticated laser systems are an integral component of an FEL facility
Multiple beamline
endstation lasersPhotocathode
laser
FEL seed lasers
Laser oscillator
Spatial profiling
Amplitude
control
Amplifier
Pulse shaping
Multiply
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
John Corlett, July 2004
Lasers may be synchronized to a common master oscillator
Photocathode laser
FEL seed lasers
Laser oscillator
Spatial profiling
Amplitude
control
Amplifier
Pulse shaping
Multiply
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Multiple beamline
endstation lasers
Laser master oscillator
John Corlett, July 2004
rf systems need to be synchronized to a common master oscillator
Photocathode laser
FEL seed lasers
Laser oscillator
Spatial profiling
Amplitude
control
Amplifier
Pulse shaping
Multiply
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Multiple beamline
endstation lasers
Laser master oscillator
~
John Corlett, July 2004
rf signals for the accelerator may also be derived from the laser master oscillator
Photocathode laser
FEL seed lasers
Accelerator RF signals
Laser oscillator
Spatial profiling
Amplitude
control
Amplifier
Pulse shaping
Multiply
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Laser oscillator Amplifier & conditioning
Multiple beamline
endstation lasers
~
~ ~ ~ ~ ~ ~
Laser master oscillator
John Corlett, July 2004
rf photocathode gun
John Corlett, July 2004
rf photocathode laser
250 300 350 400 4500
20406080
100120140
150
200
250
300
350
0 20 40 60 80100120140160
Vertical lineout
Horizontal lineout
-3 -2 -1 0 1 2 3 4 50
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Time (ps)
UV
Pow
er (
V)
File: cc120605, RMS length = 1.07 ps
UV pulse time profile
• UV pulse on cathode
• W. S. Graves, MIT-Bates (DUV FEL, Brookhaven)
John Corlett, July 2004
rf photocathode laser
• W. S. Graves, MIT-Bates (DUV FEL, Brookhaven)
50 100 150 200 250 300 350 400
20406080
100120140160180200
HeadTail
0 0.2 0.4 0.6 0.8 1 1.2 1.40
100
200
300
400
500
600
700
Time (ps)
Cur
rent
(A
)
File: phiminusg, FWHM = 0.474 ps
-3 -2 -1 0 1 2 3 4 50
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Time (ps)
UV
Pow
er (
V)
File: cc120605, RMS length = 1.07 ps
UV pulse time profile
Bunch production
, acceleratio
n, and compressi
on
• UV pulse on cathode– Non-uniformity exacerbates space-charge effects– Temporal non-uniformity induces micro-bunching
John Corlett, July 2004
Laser pulse shaping influences the emitted electron bunch
gratingstretcher
Ti:sapphireRegenerative
Amplifier
Q-switchedNd:YAG (2)
gratingcompressor
Pulse Shaper
Ti:sapphireOscillator
100 fs, 2 nJ<0.5 ps jitter
RF from master
oscillator
23>1 mJ, 800 nm, 10 kHz
PockelsCell
polarizer
photo-switch
spectral filter (computer controlled) - spatial light modulator - acousto-optic modulator
Pulse Shaper (A.M. Weiner)
Dazzler - FastLite Inc.acousto-optic dispersive filter
(P. Tournois et al.)
acoustic wave (computer programmable) - spectral amplitude - temporal phase
TeO2 crystal
Pulse Amplitude StabilizerPatent:: LLNL (R. Wilcox)
Deformable mirror
John Corlett, July 2004
Laser-driven photocathode - one of the many laser systems
H. Tomizawa, JASRI
R. Cross, J. Crane, LLNL
• Need high reliability– Integrated systems– “hot spare” system attractive– Develop techniques for pulse shaping
John Corlett, July 2004
rf gun phase and amplitude
• LUX rf gun concept as an example• Assume 5% of bunch length (1 psec) jitter• Primary drivers are launch phase, cell 1 gradient and bunch
charge (laser intensity)• Assumed uncorrelated disturbances: three most significant
parameter tolerances are (rms values):– Launch phase: 0.43 degree– Cell 1 gradient: 1.4% variation– Bunch charge: 36% variation
• Laser–1 µJ, 35 ps, 10 kHz, 266 nm–Spatial and temporal control to provide low-emittance electron bunches
• Cathode–Cs2Te
• RF field–64 MVm-1 at cathode
John Corlett, July 2004
Nominal LCLS Linac Parameters for 1.5-Å FEL
Single bunch, 1-nC charge, 1.2-Single bunch, 1-nC charge, 1.2-m m sliceslice emittance, 120-Hz repetition rate… emittance, 120-Hz repetition rate…
(RF phase: (RF phase: rfrf = 0 is at accelerating crest)= 0 is at accelerating crest)
SLAC linac tunnelSLAC linac tunnel research yardresearch yard
Linac-0Linac-0L L =6 m=6 m
Linac-1Linac-1L L 9 m9 m
rf rf 25°25°
Linac-2Linac-2L L 330 m330 mrf rf 41°41°
Linac-3Linac-3L L 550 m550 mrf rf 10°10°
BC-1BC-1L L 6 m6 m
RR5656 39 mm39 mm
BC-2BC-2L L 22 m22 m
RR5656 25 mm25 mm LTULTUL L =275 m=275 mRR56 56 0 0
DL-1DL-1L L 12 m12 mRR56 56 0 0
undulatorundulatorL L =130 m=130 m
6 MeV6 MeVz z 0.83 mm 0.83 mm 0.05 %0.05 %
135 MeV135 MeVz z 0.83 mm 0.83 mm 0.10 %0.10 %
250 MeV250 MeVz z 0.19 mm 0.19 mm 1.6 %1.6 %
4.54 GeV4.54 GeVz z 0.022 mm 0.022 mm 0.71 %0.71 %
14.1 GeV14.1 GeVz z 0.022 mm 0.022 mm 0.01 %0.01 %
...existing linac...existing linac
newnew
rfrfgungun
21-1b21-1b21-1d21-1d XX
Linac-Linac-XXL L =0.6 m=0.6 mrfrf= =
21-3b21-3b24-6d24-6d
25-1a25-1a30-8c30-8c
P. Emma, SLAC
John Corlett, July 2004
X-bandX-band XX--
Jitter tolerance budget Jitter tolerance budget for for LCLSLCLS based on the based on the many sensitivitiesmany sensitivities
Jitter tolerance budget Jitter tolerance budget for for LCLSLCLS based on the based on the many sensitivitiesmany sensitivities
rmsrms ΔΔtt-jitter-jitter = = 109 fs109 fszz jitter jitter == 14 % rms 14 % rms
……and test the budget with jitter simulationsand test the budget with jitter simulations
Jitter Tolerance Levels in the Jitter Tolerance Levels in the LCLSLCLS
Jitter simulation, tracking 10Jitter simulation, tracking 1055 particles 2000 times, where particles 2000 times, where each run is randomized in its 12 each run is randomized in its 12 main rf-parameters according to main rf-parameters according to the tolerance budgetthe tolerance budget
Jitter simulation, tracking 10Jitter simulation, tracking 1055 particles 2000 times, where particles 2000 times, where each run is randomized in its 12 each run is randomized in its 12 main rf-parameters according to main rf-parameters according to the tolerance budgetthe tolerance budget
LCLSLCLS
• P. Emma, SLAC
John Corlett, July 2004
SASE FEL output
• The SASE FEL process arises from noise
http://www.roma1.infn.it/exp/xfel/SaseXfelPrinciples/Sasexfelprinciples.pdf
Radiation intensity build-up along undulator
Half way along undulator
Saturation
John Corlett, July 2004
2.6
mm
rm
s2.
6 m
m r
ms
0.1 mm (300 fs) rms0.1 mm (300 fs) rms
Easy access to Easy access to timetime coordinate coordinate along bunchalong bunch
LCLSLCLS BC2 bunch compressor chicane BC2 bunch compressor chicane (similar in other machines)(similar in other machines)
xx , h
oriz
onta
l pos
. (m
m)
, ho
rizon
tal p
os.
(mm
)
zz, longitudinal position (mm), longitudinal position (mm)
50 50 mm
Slit spoiler defines radiating region of bunch
Paul Emma, SLAC
John Corlett, July 2004
Add thin slotted foil in center of chicaneAdd thin slotted foil in center of chicane
1-1-m emittancem emittance
5-5-m emittancem emittance
1-1-m emittancem emittance
AFTER FOILAFTER FOIL
BEFORE FOILBEFORE FOIL
Paul Emma, SLAC
John Corlett, July 2004
Timing determination from Electro Optic sampling -developing techniques at the SPPS
Er
Principle oftemporal-spatial correlation
Line image camera
polarizer
analyzer
EO xtal
seconds, 300 pulses: z = 530 fs ± 56 fs rms Δt = 300 fs rmsseconds, 300 pulses: z = 530 fs ± 56 fs rms Δt = 300 fs rms
single pulse
A. Cavalieri
centroidwidth
John Corlett, July 2004
ESASE - Enhanced Self-Amplified Spontaneous Emission
BunchingAcceleration SASE
70 as70 as
Modulation
A. Zholents - Wednesday
John Corlett, July 2004
P0 = 235 GWWith a duty factor = 40,
Paverage~ 6 GW
70 as
• Each micro-pulse is temporally coherent and Fourier transform limited
• Carrier phase is random from micro-pulse to micro-pulse • Pulse train is synchronized to the modulating laser
L=800 nm
x-ray macropulse
Enhanced Self-Amplified Spontaneous Emission
John Corlett, July 2004
Dispersive section strongly increases bunching at fundamental
wavelength and at higher harmonics
In a downstream undulator resonant at 0/n, bunched beam strongly
radiates at harmonic via coherent spontaneous emission
nπ-nπphase
energ
y
-π π
Input Outpute-beam phase space:
Energy-modulate e-beam in undulator via FEL resonance with coherent input radiation
Harmonic generation scheme -coherent source of soft x-rays
L.-H. Yu et al, “High-Gain Harmonic-Generation Free-Electron Laser”, Science 289 932-934 (2000)L.H. Yu et al., "First Ultraviolet High Gain Harmonic-Generation Free Electron Laser", Phys. Rev. Let. Vol 91, No. 7, (2003)
modulator radiatorbunching chicane
laser pulse
e- bunchDeveloped and demonstrated by L.-H. Yu et al, BNL
John Corlett, July 2004
seed laser pulse modulator 3rd - 5th harmonic radiator
modulator 3rd - 5th harmonic radiator
Cascaded harmonic generation scheme
Delay bunch in micro-orbit-bump (~50 m)
Low electron pulse
Unperturbed electrons
seed laser pulse
tail head
radiator radiatormodulatormodulator
disrupted region
John Corlett, July 2004
User has control of the FEL x-ray output properties through the seed
laser • OPA provides controlled optical seed for the free electron laser
• Wavelength tunable – 190-250 nm
• Pulse duration variable– 10-200 fs
• Pulse energy– 10-25 µJ
• Pulse repetition rate– 10 kHz
• Endstation lasers seeded by or synchronized to Ti:sapphire oscillator
– Tight synchronization <20 fs
Ti:sapphireOscillator
<100 fs, 2 nJ<50 fs jitter
gratingstretcher
Ti:sapphireRegenerative
Amplifier
Q-switchedNd:YAG (2)
gratingcompressor
RF derived from optical from master
oscillator
~1 mJ, 800 nm, 10 kHz
Optical Parametric Amplifier
>10% conv. efficiency
e-beam
laser seed pulse
undulator undulator
undulator harmonic
n undulator stagesx-ray
Endstation synch.
John Corlett, July 2004
Gas jet
Seeding with XUV from high harmonics in a gas jet (HHG)
• Coherent EUV generated up to ~ 550 eV– R. Bartels et al, Science 297, 376 (2002), Nature 406, 164
(2000)
H. Kapteyn, JILA/Uni. Colorado/NIST
E field
Harmonic emission
302520151050Time(fs)
I. Christov et al, PRL 78, 1251, (1997)
45 39 29 25 17Harmonic order
67.5eV 25.5eV
J. Zhou et al, PRL 76(5), 752-755 (1996)
John Corlett, July 2004
Seeding multiple cascades from a single electron bunch allows 10 kHz operation in
LUX concept
• Optical pulses overlap different part of bunch for each beamline• Timing jitter influences number of cascades that can be served
by a single bunch• CSR effects in the arcs introduce ~ few fs jitter for ~ few %
charge variation
e-beam
FEL optical pulses
John Corlett, July 2004
800 nm
spectral broadening and
pulse compression
e-beam
harmonic-cascade FEL
two period wiggler tuned for FEL
interaction at 800 nm
2 nm light from FEL
2 nm modulator chicane-buncher
1 nm radiator
dump
endstation
1 nm coherent radiation e-beam
endstation
time delay chicane
Laser-manipulation produces attosecond x-ray pulses in harmonic
cascade FEL
e-beam
A. Zholents, W. Fawley, “Proposal for Intense Attosecond Radiation from an X-Ray Free-Electron Laser”, Phys. Rev. Lett. 92, 224801 (2004)
John Corlett, July 2004
Ultrafast x-ray pulses by electron bunch manipulation and x-ray compression
2 ps
~ 50 fs
RF deflecting cavity
Electron trajectory
in 2 ps bunch
John Corlett, July 2004
Master Oscillator Laser
Δt Δt
electron bunch
laser pulse
x-rays
RF
crab cavity3.9 GHz
x-ray pulse compressionasymmetric Bragg x-tals
Δy
Δt
ΔyLow-noise
Amp3.9 GHz
• Synchronization dependent on phase of deflecting cavity• Phase lock to master oscillator
• Fast feedback systems around scrf• Extend frequency response of the system
Synchronize deflecting cavities and pump laser for hard x-ray production
John Corlett, July 2004
Typical end station concept
Precisely timed laser and linac x-ray pulses
Linac x-ray pulse
Laser master
oscillator pulse
End station
Pulse diagnosticsLaser and delay lines
~ 10 m
Modelocked
Oscillator
• Active laser synchronization– Independent oscillators at each
endstation– Complete independence of endstation
lasers– Wavelength, pulse duration,
timing, repetition rate etc.
John Corlett, July 2004
Ti:sapphire
Oscillator<100 fs, 2
nJ<50 fs jitter
gratingstretcher
Ti:sapphire
Regenerative
Amplifier
Q-switchedNd:YAG (2w)
gratingcompressor
>1 mJ, 800 nm, 10 kHz
Optical Parametri
c Amplifier
Beamline endstation lasers
PCPC
/4
typical regenerative amplifier
~20 passes ΔL=1 µm (Δt=66 fs)
• interferometric stabilization• cross-correlate with oscillator (compress first)• temperature stabilize (Zerodur or super-invar)
chirped-pulse amplification
RF derived from optical
master oscillator
John Corlett, July 2004
All-optical timing system to achieve synchronization between laser pump and x-
ray probe• Laser-based timing system• Stabilized fiber distribution system• Interconnected laser systems
• Active synchronization • Passive seeding• rf signal generation 20–50 fs synchronization
Photo InjectorLaser
RF cavity
Master OscillatorLaser
FELSeed Laser
MultipleBeamline Endstation
Lasers
FELSeed Laser
Linac RF
Optical fiber distribution network
John Corlett, July 2004
cw reference laserinterferometer
L~100 m
Path Length ControlΔL= 2 m
Δt= 7 fs
Agilent 5501B210-9 one hour (Δ210-8 lifetime
Beamline 1
Beamline 2
fiber-based system EDFA(fiber amp)
PZT controlpath length
EDFA(fiber amp)
Master Oscillator
Timing distribution
positiondetector
positiondetector
Master Oscillator
cw reference laserinterferometer
Beamline 2
Beamline 1
free-space system (in vacuum)
John Corlett, July 2004
cw reference laserinterferometer
L~100 m
Path Length ControlΔL= 2 m
Δt= 7 fs
Agilent 5501B210-9 one hour (Δ210-8 lifetime
Beamline 1
Beamline 2
fiber-based system EDFA(fiber amp)
PZT controlpath length
EDFA(fiber amp)
Master Oscillator
Timing distribution - fiber systems developed fro distribution of frequency
standards
2
4
6
80.1
2
4
6
81
2
4
6
Jitter spectral density (fs / Hz
1/2
)
101
102
103
104
105
106
107
Fourier Frequency (Hz)
1
2
3
4
56
10
2
3
4
56
100
Integrated jitter (fs)
4 km DSF in lab, unstabilized 4 km DSF in lab, stabilized
Integrated jitter
Mixer/amplifier noise floor
D. Jones, UCB/JILA
John Corlett, July 2004
Modelocked fiber laser oscillatorrf stabilized
28 dB AMP
RF Clock1.3/n GHz
Amplifier
LPF
error signal
17 dBm mixer
Modelocked Laser1.3 GHz
Trep
BPF 1.3 GHzf1/Trep
Modelocked Fiber Laser Oscillator – RF Stabilized
• Phase-lock all lasers to master oscillator• Derive rf signals from laser oscillator• Fast feedback to provide local control of accelerator rf
systems Synchronization 10’s fs
John Corlett, July 2004
SummaryLasers, timing,and synchronization
• Laser systems under development at many institutions • Applications for improved light-source operations
• Photocathode laser, timing system master oscillator, FEL seed laser, endstation pump laser
• Manipulation of e- beam by laser has great potential• HHG power increasing, wavelength decreasing
• Ultra-stable timing systems with optical fiber distribution systems under development • Application of techniques to accelerator environments
and requirements is to be demonstrated • 10’s fs synchronization seems achievable