1. Pre-stabilized laser (PSL) for AdV Scope of the system Main tasks Requirements Reference solution and status of the design Plans towards completion Technical issues Conclusion 1AdV 1st review 3-4/11/08 Catherine Nary MAN C.N.Man

2. Scope of the PSL system AdV 1st review 3-4/11/08 2C.N.Man High power lasers system of 200W, pre-stabilized in frequency and power stabilized  noise level required at entrance of IMC IMC PSL system

3. Main tasks AdV 1st review 3-4/11/083 The high power laser(s) the injection locking optics and electronics. The frequency pre-stabilization loop the fast electronics utilized in that loop A triangular pre-mode-cleaner (PMC) the control electronics. The power stabilization of the laser the control loop and vacuum photodiode The positioning of the optical elements on the laser bench Matching and steering optics modulators (EOM) and Faraday isolators (FI) Monitoring photodiodes C.N.Man

4. Requirements C.N.ManAdV 1st review 3-4/11/084 RequirementValueFreq. range Power 200 W Frequency noise linear spectral density * f > 10 Hz Power noise RIN (−170 dB/ √ Hz) ** 10 Hz< f <10 kHz Beam jitter *** Beam geometry High order modes content <5% * to be refined by Interf Sensing Control (ISC) system ** assume contrast of 0.01% and arm finesse of 900, to be refined *** need 1 nrd/ √ Hz & assume IMC filtering factor of 1000 NB: Virgo+ will also help refining the specs as it will serve too as testbed for some technological choices

5. Baseline design AdV 1st review 3-4/11/085C.N.Man 1-2W 20W 50W 200W

6. Rigid reference cavity LF itf lock Control Strategies AdV 1st review 3-4/11/086 HP slave 200W Inj L2 MP slave 20W Inj L1 Master 1-2W RIN L Suspended IMC Freq pre-stab C.N.Man Pre-mode cleaner pmc lockIMC lock 3kms baseline cavity Power stab

7. Plan towards completion 7AdV 1st review 3-4/11/08C.N.Man 1/ Refine stabilizations requirements: a few outputs from other systems asap: ISC  if DC detection is confirmed, simplify pmc design & power stabilization alignments performances predictions give residual beam jitter required locking precision gives residual RIN in LF and in detection range OSD  asymmetry (freq stab), contrast (power stab), … a trade-off to find 2/ Order HP stage for tests in lab: noise spectrum, beam quality and jitter, … 3/ Pre-mode-cleaner realization (depends on HP beam quality and amplitude noise) 4/ Power stabilization (check of real performances in LF range going on) 5/ Frequency stabilization (after IMC completion)

8. Tasks towards completion C.N.ManAdV 1st review 3-4/11/088 topicsrequirementsprocurementsR&D realization Tests/commission.

9. Technical issues C.N.ManAdV 1st review 3-4/11/089 Can we skip the 20W medium power stage ? Injection locking  noise of the master inside locking range could be done during the development of injection lock loop Option of using 200W fiber amplifier : 200W class, to be tested in 2009, much cheaper than SSL tests & controls to be done Option of using fiber to transport HP beam to Injection bench under study Combination of the 2 options in an all-fibered PSL can make the PSL schematic evolve certainly in a simpler way

10. Conclusion C.N.ManAdV 1st review 3-4/11/0810 The baseline solution of this SubSystem shows no surprise From Virgo+ to AdV, the main change is the replacement of 50W HP stage by 200W stage. Virgo+ is an intermediate step for testing some improvements that would help refine the requirements AdV PSL is a simple extrapolation of Virgo & Virgo+ If necessary some performances can be improved Still some requirements need to be refined by other SS This SS is not on the critical path and can evolve even during the commissioning phase.