40m Modeling and Experiment 1 Modeling the 40m QND Workshop, Hannover Dec 15, 2005 Robert Ward Seiji...
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Transcript of 40m Modeling and Experiment 1 Modeling the 40m QND Workshop, Hannover Dec 15, 2005 Robert Ward Seiji...
40m Modeling and Experiment 1
Modeling the 40m
QND Workshop, HannoverDec 15, 2005
Robert Ward
Seiji Kawamura, Osamu Miyakawa, Hiro Yamamoto, Matthew Evans, Monica Varvella
40m Modeling and Experiment 2
Modeling tools used at the 40m
Twiddle» Frequency domain, analytical, no radiation pressure
Finesse » Frequency domain, no radiation pressure
E2E » Time domain, now with classical radiation pressure
TCST (Thomas Corbitt Simulation Tool)» Two-photon formalism, frequency-domain
Optickle» Frequency domain, Matlab, two-photon formalism
40m Modeling and Experiment 3
Finesse
0 50 100 150 200 250 300 3500
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Demodulation Phase of f1
Dem
odul
atio
n Pha
se o
f f2
Double Demodulation at SP- 0.4
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dc=0l+l-ls
Dem
odu
latio
n P
hase
of
f2
Lockingpoint
Finesse used extensively at the 40m lab 2004-2005
Seiji Kawamura modeled the DRMI very thoroughly using Finesse
Very useful for investigating quirks of double & differential demodulation
40m Modeling and Experiment 4
Differential Demodulation:offset vs gain
40m Modeling and Experiment 5
Finesse
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-80
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dB m
ag
CARM response
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150P
hase
f (Hz)
•Also used to investigate the coupled cavity response in our offset CARM state, and design compensation.
•Unfortunately has no radiation pressure effects
40m Modeling and Experiment 6
Straight from the ilog
Location of peak RSE response (in CARM) as a function of offset, modeled in Finesse, and then measured.
40m Modeling and Experiment 7
Dynamic compensation filterfor CARM servo
Optical gain of CARMOpen loop TF of CARM• Optical gain (normalized by transmitted power) shows moving peaks due to reducing CARM offset.
• We have a dynamic compensative filter having an nearly the same shape as optical gain except for upside down. Designed using FINESSE.
• Open loop transfer function has no phase delay in all CARM offset.
40m Modeling and Experiment 8
Error signal sweeps at 10-9 m/s for the 40m IFO obtained in
E2E framework and compared with TWIDDLE predictions
Example:DARM @ AP 166 MHz
TWIDDLE and E2E comparison
e2e SIMULATION:4Om/AdvLIGO package
TWIDDLE
E2E
40m Modeling and Experiment 9
e2e SIMULATION: 4Om/AdvLIGO package
Comparison between real data (black) and e2e simulated data (red) of the transmitted light for both the arms (full IFO): the mirror velocities used in
E2E simulation are the values obtained fitting the real data
Real data have been used to estimate relative mirror velocity for
both the arms:
Vxarm= (0.35 ± 0.13) μm/s
Vyarm= (0.26 ± 0.13) μm/s
E2E
E2E
real data
real data
Tr X
Tr Y
40m Modeling and Experiment 10
e2e SIMULATION: 4Om/AdvLIGO package
Comparison between real data , e2e simulated data and the
theoretical prediction V(t) of the SP error signal @ 166 MHz
The τ and the velocity v is the value obtained fitting real data
τ = 0.7 msv = 0.26 μm/s
V(t) ~ exp(t/τ) sin( a t2)
with a = (k v) / (2 T)
40m Modeling and Experiment 11
E2E: 40m Lock Acquisition
Simulation indicates that controlled reduction of CARM offset should work.
E2E simulation by Matthew Evans in June 2005
40m Modeling and Experiment 12
Optical spring in E2E
• Calculated by time domain simulation
• No length control• Lock lasts ~0.7sec, so
statistics at low frequency is not good.
• Simple length control required
• Calculation time ~5min using DRMI summation cavity
Hiro Yamomoto
40m Modeling and Experiment 13
E2E DARM TF to I and Q
•5W Input•Arms controlled with POX, POY (no DARM)•no MICH control
Hiro Yamomoto
40m Modeling and Experiment 14
E2E Optical Noise
40m Modeling and Experiment 15
Optical noise of 40m in E2E
• Simple length control (UGF~100Hz)
• Err2/(Err1/DARM) DARM: DARM excitation on mirrorsErr1: error signal with DARM
excitationErr2: error signal with optical noise
• How much further does E2E need to go? 2-photon?
• input vacuum?• Quantum control?• Or just classical physics +
shot noise + radiation pressure noise ?
Err2/(Err1/DARM)
40m Modeling and Experiment 16
TCST
102
103
80
90
100
110
120
130
140CARM optical springs at different CARM offsets
f (Hz)
CA
RM
opt
ical
res
pons
e (d
B)
Arm power = 6
Arm power = 8Arm power = 10•Solid lines are from TCST
•Stars are 40m data•Max Arm Power is ~80•Also saw CARM anti-springs, but don’t have that data
40m Modeling and Experiment 17
Optickle
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f (Hz)
dB (
a.u.
)
DARM Response
40m DataOptickle
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f (Hz)
dB (
a.u.
)
DARM Response
40m DataOptickle
40m Modeling and Experiment 18
CARM optical springs, with no offsets (TCST)