Transcript Document 7916807

The Optickle
Optical Modeling Tool
QND Workshop, Hannover
Dec 15, 2005
Robert Ward & Matthew Evans
Optickle
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Optickle: Frequency Domain
IFO Simulation
 Optickle is a new frequency domain IFO modeling
tool:
» Written in Matlab
– Matlab allows easy integration to other modeling efforts (a frequencydomain e2e, like LinLIGO)
– Easily Extensible
– Uses Matlab classes for generality
» Uses the methods outlined in T. Corbitt et al: “Mathematical
framework for simulation of quantum fields in complex
interferometers using the two-photon formalism” (LIGO-P030071-00R) to
calculate the IFO opto-mechanical frequency response.
» Designed for concrete units (Watts, meters, Hz)
Optickle
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Optickle example: FP cavity
 Includes losses, AR coatings, pickoff fractions, mass
 Build an arbitrary IFO using Optickle class methods:
» addOptic
» addLink
100
[mf, mDC1, E_dc] = propFieldsP(opt,f,offsets,Lfield);
bm = getIndexP(opt,snEX,'pos',0);
b2f = getIndexP(opt,snIX,'b',2);
exc = zeros(size(mf,1),length(f));
exc(bm,:) = 1;
resp = fmult(mf,exc);
mybodeplot(f,resp(b2f,:));
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60
40
180
135
90
Phase (deg)
% create model
opt = Optickle;
% add optics
[opt, snIX, nIX_HR, nIX_AR] = ...
addOptic(opt, 'IX', 0.005, 00e-6, 0e-3, 0e-6, 0e-6, 4e2, 0, 10);
[opt, snEX, nEX_HR, nEX_AR] = ...
addOptic(opt, 'EX', 10e-6, 00e-6, 0e-3, 0e-6, 0e-6, 4e2, 0, 10);
% add links
opt = addLink(opt, snIX, 1, nEX_HR);
opt = addLink(opt, snEX, 1, nIX_HR);
Mag (dB)
 Example:
45
0
-45
-90
-135
-180
0
10
Optickle
1
10
2
10
Frequency (Hz)
3
4
10
10
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Optickle Example: FP cavity
 Response of front
mirror to back mirror
‘excitation’
 1 nm detune
 finesse ~ 1200
0
Mag (dB)
-50
-100
-150
-200
180
1
100
10000
100000
100000000
135
Phase (deg)
90
45
0
-45
-90
-135
-180
0
10
1
10
Optickle
2
10
Frequency (Hz)
3
4
10
10
4
Optickle Example: AdLIGO
Mag (dB)
180
160
140
120
100
180
135
90
Phase (deg)
•40 kg Test Masses
•15W Input Power
•85 degree detune
•70ppm loss mismatch
DC Readout GW response, W/m
3pm DARM offset, 70ppm mismatch
45
0
-45
-90
-135
-180
-2
10
Optickle
-1
10
0
10
1
2
10
10
Frequency (Hz)
3
10
4
5
10
10
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Optickle Example: AdLIGO
Easy to create a
frequency dependent
coupling matrix, useful
for, e.g., estimating the
contribution of loop
noise to DARM.
Normalized row of DC readout signal matrix
40
CARM
PRC
SRC
MICH
20
0
-20
dB mag

-40
-60
-80
-100
-120
-2
10
Optickle
0
10
2
10
f (Hz)
4
10
6
10
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Optickle status
Current:
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Free masses (no pendulum yet)
Carrier and signal sidebands only (no RF sidebands)
No servos
No beamsplitters (-> incorrect radiation pressure at BS)
Plane waves
No input vacuum fields
Future:
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Validation against theoretical calculations
Pendulum response for masses (quad?)
more high level methods (addSignal, addPD, addRFsideband, etc).
RF detection (no radiation pressure on RF sidebands?)
Vacuum noise
Force to position
servos?
Hermite Gaussian?
Optickle
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