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Recent results of the femto-second synchronization system Florian Löhl December 20 th

Recent results of the femto-second synchronization system Florian Löhl December 20 th. Optical timing system. to low level RF. optical length stabilized fiber links. laser to RF conversion. fiber couplers. Master Laser Oscillator (erbium-doped fiber laser).

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Recent results of the femto-second synchronization system Florian Löhl December 20 th

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  1. Recent results of the femto-second synchronization system Florian Löhl December 20th

  2. Optical timing system to low level RF optical length stabilized fiber links laser to RF conversion fiber couplers Master Laser Oscillator (erbium-doped fiber laser) • direct use of laser pulses • beam arrival-time monitors • beam position monitors • optical down-converters • seeding of amplifiers • synchronization of other • lasers (cross correlation) • … phase lock loop low-noise microwave oscillator Florian Löhl XFEL Meeting, December 20th

  3. Current projects(Coordinator: H. Schlarb) Master laser system (MLO) (A. Winter, MIT) Fiber link stabilization (F. Loehl, MIT) Laser to RF conversion (F. Ludwig, B. Lorbeer, M. Felber, MIT) Bunch arrival time monitor (F. Loehl) BPMs in magnetic chicanes (K. Hacker) New down-converter for cavity regulation (F. Ludwig, M. Hoffmann, LLRF-Group) Laser oscillator for CPA system (ORS) (N. Javahiraly, A. Winter) Fast motor control and position encoder readout (J. Thomas, …) DOOCS compatible laser diode driver (A. Winter, FEB, MVP) Digital regulation of master laser system (W. Jalmuzna, LLRF-Group) Digital regulation of fiber links (G. Petrosyan, …) Drift characterization of photo diodes (B. Lorbeer, F. Ludwig, …) Drift reduced RF mixer (J. Mueller, F. Ludwig) DOOCS compatible polarization controller (M. Felber, …) Fast regulation of cavities with beam based measurements (LLRF-Group) Development of precise photo diode read out (K.H. Matthiesen, …) Cross-correlation of pump-probe laser and timing system (V. Arsov, …) Development of analog PI controller / piezo driver (N. Ignachine, …) Design of 130 MHz ADC board (DWC, BAM, BPM) (P.Strzalkowski, M. Hoffmann, …) Characterization of EDFAs (J. Mueller) Simulation of optical pulse propagation (H. Schlarb, F.Loehl...) Florian Löhl XFEL Meeting, December 20th Göttlicher analog, Eckelmann FPGA, G. Petrosyan Doocs server, Vetrov digital part)

  4. Master laser oscillator (MLO) • Dispersion managed stretched pulse fiber-laser • Gain medium Erbium, (center at 1550 nm) • High pulse energy (up to ~ 1 nJ) • Pulse duration: ~ 100 fs FWHM • Repetition rate: 54 MHz • Integrated timing jitter (1 kHz – 20 MHz) ~ 10 fs • Integrated amplitude noise (10 Hz – 1 MHz): 0.03 % Courtesy of A. Winter Florian Löhl XFEL Meeting, December 20th

  5. Master laser oscillator (MLO) Courtesy of A. Winter Florian Löhl XFEL Meeting, December 20th

  6. Fiber link stabilization Florian Löhl XFEL Meeting, December 20th

  7. Fiber link stabilization Florian Löhl XFEL Meeting, December 20th

  8. Fiber link stabilization Timing jitter: ~ 9.7 fs Timing jitter: ~ 9.2 fs Detector noise floor: ~ 8.2 fs Florian Löhl XFEL Meeting, December 20th

  9. Fiber link installation P7 P5 P8 P6 P10 P1-10 P4 P9 • Optical fiber test section will be installed in Hall 1 • test of specialty fibers • development of fiber link stabilization • Installation status: • Installation of pipes is already done or will be done this week • Installation of first optical fibers to be done first week of January • Splicing planned for January / February Installation of optical fibers in the TTF linac Top view P3 P2 P1 Synchronization hutch (start point of all links) fiber patch panel Florian Löhl XFEL Meeting, December 20th

  10. New fiber laser development from MIT:194 MHz laser (potentially scaleable to > 500 MHz) 1 Hz – 1MHz: 0.004 % FWHM 167 fs 1 kHz – 10 MHz: 29 fs Cortesy of Jeff Chen Florian Löhl XFEL Meeting, December 20th

  11. Laser to RF conversion Low noise DRO (f = n*frep) resonator laser pulses PD phase shifter ~ ~ ~ t laser pulses Optical division of distributed frequency AOM / EOM frep / n frep modulation voltage f = n*frep • Direct conversion with PD • temperature drifts • AM to PM conversion* • noise limitation due to low power in spectral line of PD output laser pulses PD BPF frep f = n*frep • Injection Locking • temperature drifts of PD • AM to PM conversion of PD* • DRO determines high frequency noise • entire photo detector signal used f = n* frep frep (*) typical AM to PM conversion: 1-10ps/mW Florian Löhl XFEL Meeting, December 20th

  12. Laser to RF conversion:sagnac loop Phase detection in the optical domain: Cortesy of F. Ludwig Florian Löhl XFEL Meeting, December 20th

  13. Laser to RF conversion:sagnac loop Phase detection in the optical domain: modulation voltage: frep / 2 Cortesy of F. Ludwig Florian Löhl XFEL Meeting, December 20th

  14. Laser to RF conversion:sagnac loop Phase detection in the optical domain: VCO signal to stabilize (n*frep) modulation voltage: frep / 2 Cortesy of F. Ludwig Florian Löhl XFEL Meeting, December 20th

  15. Laser to RF conversion:sagnac loop Phase detection in the optical domain: VCO signal to stabilize (n*frep) modulation voltage: frep / 2 Cortesy of F. Ludwig Florian Löhl XFEL Meeting, December 20th

  16. Laser to RF conversion:sagnac loop Low noise PI controller (P, I, g, cutoff independent) Optical to RF Detector 1 MLO RF electronic 1 RF Phase Detector (0.8fs @10GHz) Optical to RF Detector 2 RF electronic 2 Florian Löhl XFEL Meeting, December 20th

  17. Laser to RF conversion:sagnac loop timing jitter between two VCOs locked via sagnac loop (10 Hz – 10 MHz): 12.8 fs @ 10 GHz long term drift between the two VCOs: 48 fs over 1 hour (top) Base line drifts (one VCO connected to same mixer): 50 fs over 8 hours (bottom) Cortesy F. Ludwig Florian Löhl XFEL Meeting, December 20th

  18. Drift reduced RF mixer Courtesy of F. Ludwig, J. Mueller Florian Löhl XFEL Meeting, December 20th

  19. Drift reduced RF mixer Florian Löhl XFEL Meeting, December 20th

  20. New down converter for cavity regulation RF-input 1 BPF BPF Regulation loop Lookup Table I samples I,Q-Detection LNA ADC Q samples Local RF-Generator ADC clock LO-input Noise appears at the DWC output but not on the cavity field! • 250 kHz switched system •  54 MHz CW system: • uses 54 MHz intermediate frequency • gives together with the high ADC sampling rate the possibility of averaging (reduces noise at high frequencies) • change from active to passive mixers while increasing the power level will reduce also the noise at low requencies Courtesy of F. Ludwig, LLRF-Group Florian Löhl XFEL Meeting, December 20th

  21. New down converter for cavity regulation ADC noise reduction by averaging: fS = 81 MHz, fIF = 54 MHz, ∆t = 1μs Courtesy of M. Hoffmann, LLRF-Group Florian Löhl XFEL Meeting, December 20th

  22. Bunch arrival time monitor (BAM) sampling time of ADC 40.625 MHz (54 MHz) The timing information of the electron bunch is transferred into a laser amplitude modulation. This modulation is measured with a photo detector and sampled by a fast ADC. Florian Löhl XFEL Meeting, December 20th

  23. Bunch arrival time monitor (BAM) • Jitter between two adjacent bunches: ~ 40-50 fs • Timing resolution with respect to reference laser: < 30 fs Arrival time measurement for all bunches in the bunch train possible!  Plan to implement this into feedback system of LLRF group Florian Löhl XFEL Meeting, December 20th

  24. Bunch arrival time monitor (BAM) 1.2mm thick Alumina disk 17mm 6.2mm 14.5mm • The signal of the ring pick-up shows a “bump” around the zero-crossing. This bump has a large • orbit dependence. • New design of pick-up (knobs instead of a ring) (design: K. Hacker) Installation of a first test pick-up is scheduled for January 2007. pick-up currently used: new design: Florian Löhl XFEL Meeting, December 20th

  25. BPMs in the magnetic chicanes BPM Tapering Pickup Channel Beam Path SMA Vacuum Feedthrough Compact! The arrival time of the pickup signals is measured at both ends with the same technique as used for the bunch arrival time monitor. The beam position is determined from the difference of both arrival times. Courtesy of K. Hacker Florian Löhl XFEL Meeting, December 20th

  26. BPMs in the magnetic chicanes R16 T166 R1666 ACC1 energy change [%] Measurements done with scope in the tunnel (~ 150 μm resolution) Blue lines show expected beam position for different energies Agreement between simulated pick-up response (40 GHz, blue) and measured one (8 GHz scope, red) Courtesy of K. Hacker Florian Löhl XFEL Meeting, December 20th

  27. Regulation of injector using beam based measurements Booster Chicane BPM (CBPM) Photo Cathode Laser synchrotron light monitor (C. Gerth) 1 arrival-time monitors RF Gun 2 3 BPMs bunch compression monitor (H. Delsim-Hashemi, B. Schmidt) • Regulation parameters: - photo cathode laser: arrival time • - Gun: phase (amplitude not critical) • - ACC1: phase, amplitude • Goal: stable bunch compression and arrival time • Many different monitor systems and complex regulation algorithms needed! • Arrival time of photo cathode laser pulses (1st arrival time monitor) • Phase of RF gun (difference between 1st and 2nd arrival time monitor) • Amplitude of booster module (CBPM + BPMs) • (synchrotron light monitor + BPMs) • (difference between 3rd and 2nd arrival time monitor) • Phase of booster module (bunch compression monitor) • (fiber laser + EO) Florian Löhl XFEL Meeting, December 20th

  28. New infrastructure Florian Löhl XFEL Meeting, December 20th

  29. Conclusion • Collaboration with MIT is VERY fruitful • A lot of infrastructure for synchronization R&D is already installed • Great effort done by many people and groups to reach the goal of a femto-second stable machine • Demonstration of many schemes is already done • next big step: construction of complete system (end 2007, completed 2008) • performance test of complete system Many thanks for the technical support of the FLA group and for the fruitful collaboration with the LLRF-group! Florian Löhl XFEL Meeting, December 20th

  30. Optical link EDFA laser CEO + CW locked fr/(2n) fr/(2n) Er-fiber laser Slow phase shifter Fast phase Modulator ODL PZT Temperature stabilized dispersion compensation module 50MHz PZT Pump RF detector Bal. SHG Det. f0 fr EDFA Mixer  Digital FB controller Bal. Coh. Det. Digital FB controller  HeNe/CH4 Mirror 2.5MHz  SMF 0.625MHz 3.39um 10MHz Seed/PP laser AOM HNLF Ti:Sa CEO stab. & HeNe/CH4 stab. InSb 77K BP PPLN PPLN fr 2.2um :100 PD LiIO3 BP 1.1um FB controller  BP 1100nm /2c 62.5MHz Bal. Coh. det 1GHz      ~ ~ ~

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