<> --------- = Purpose of the upgrade = --------- == To demonstrate AdvLIGO interferometer technologies == === ►Prototyping of AdvLIGO LSC === * '''Lock acquisition''' * "Prove AdvLIGO LSC actually works" * [=> Link to 40m lock acq][=> Link to AdvLIGO LSC scheme] * '''Green laser locking''' [=> Link to 40m ALS][=> Link to AdvLIGO ALS] * "Realize lock of the arms independently from the main beam" * "Achieve semi-deterministic lock & smooth handing off" * '''Noise mechanisms / DC readout''' * "Discover and/or confirm by a model RSE specific noise couplings" === ►Tuned / Detuned RSE comparison === * "Clarify advantage and disadv. of the tuned/detuned configuration" * "Demonstrate smooth transition" === ►RGC based digital control system === * "Demonstrate complicated LSC code on the connected multiple systems" * "Establish rapid prototyping methods with simulated plants on the processors" * [=> Link to 40m CDS][=> Link to AdvLIGO CDS] --------- == To do anything useful to make the AdvLIGO easier / faster == === ►DC&Dither technologies === * Offset lock and handoffs * AF WFS technique * "Develop and characterize various new useful techniques" === ►Interferometer Diagnosis === * Cavity characterization using aux. laser injection * "Provide a method of precise in-situ characterization of the interferometer" === ►Development / test bench of advanced technologies === * GigE CCD WFS technique * Adaptive noise cancellation [=> Link to 40m ASS] * "Demonstrate how it works" * "Understand and improve its limitations" --------- = Major things to be upgraded = --------- === ►Interferometer design === * AdvLIGO like optical configuration / sensing scheme * Arm finesse of about 450 * 2 Phase modulations (11MHz & 55MHz), no Mach Zehndar * Longer PRC/SRC => Use of Folding mirror * PR gain decided for carrier, SR gain decided by sensitivity * Small asymmetry, extraction of f2 by a undercoupled SEC => good through put of f2 to the dark port * Use of third harmonic demodulation scheme * Links to [Optical Configuration][Power Budget][Optical Layout][PRC/SRC design][Sensing scheme][Lock Acquisition scheme] * Smaller ITMs/ETMs for lower the optical spring frequencies * Tuned or detuned? * Tuned / offset detuning What should be compared? === ►Green laser locking === * Arm length stabilization using auxiliary 532nm lasers at the end of each arm. * Dichroic coating (1064nm/532nm) for ITMs and ETMs * Link to [Green locking] === ►CDS (Control and Data System) === * AdvLIGO style digital control system utilizing Matlab/Simulink (Realtime Code Generator) * Realtime code development with "virtual interferometer" * First test for Realtime code development with "virtual interferometer" * Links to [CDS upgrade] === ►Mechanics === * Use of Tip-Tilt suspenions which is similar to one for ELIGO and AdvLIGO * Use of Small Optics Suspensions for ITMs/ETMs. * Links to [Suspension upgrade] === ►Electronics === * Upgrade of the RF detection systems * PDs/demodulators/RF distributors * Use of a multiple resonant EOM * Links to [Electronics upgrade] ---------