1. LIGO- G040279-00-R Telecon on June, 15. 2004 1 Mach-Zender interferometer to eliminate sidebands of sidebands for Advanced LIGO Osamu Miyakawa, Caltech LIGO- G040279-00-R

2. Telecon on June, 15. 2004 2 Signal extraction of AdvLIGO  Two sidebands are used to separate arm cavity signals and Central part (Michelson, PR, SR) signals.  Arm cavity signals are extracted from beat between carrier and f 1 or f 2.  Central part (Michelson, PR, SR) signals are extracted from beat between f 1 and f 2, not including arm cavity information. f1f1 -f 1 f2f2 -f 2 Carrier(Resonant on arms) Single demodulation Arms information L + and L  Double/differential demodulation Central part information l +, l  and l s

3. LIGO- G040279-00-R Telecon on June, 15. 2004 3 Sidebands of sidebands  Sidebands of sidebands are produced by two series EOMs.  Beats between carrier and f 2 +/  f 1 disturb central part.  Sidebands of sidebands are amplitude modulation. Simulation Real world f1f1 -f 1 f2f2 -f 2 Carrier f1f1 -f 1 f2f2 -f 2 Carrier

4. LIGO- G040279-00-R Telecon on June, 15. 2004 4 l + signal with sideband of sideband  No offset  Big disturbance by carrier  Some small disturbance Carrier resonance No offset

5. LIGO- G040279-00-R Telecon on June, 15. 2004 5 Signal matrix  Original signal matrix  Signal matrix with sideband of sideband

6. LIGO- G040279-00-R Telecon on June, 15. 2004 6 What should we do?  Continue this optical setting with sidebands of sidebands?  Change experimental setup to kill sidebands of sidebands?

7. LIGO- G040279-00-R Telecon on June, 15. 2004 7  Mach Zehnder interferometer »1/2 modulation index (1/4 sideband power) »Need one more control »Amplitude noise, frequency noise  Michelson interferometer »Same modulation index as series EOMs »Faraday-isolator »Need one more control »Amplitude noise, frequency noise  2 more AOM to kill 133MHz and 199MHz »1/2 carrier power »Need to adjust phase and amplitude  Using a broad band EOM to kill 133MHz and 199MHz »Not easy to kill amplitude modulation To eliminate sidebands of sidebands PD FI EOM

8. LIGO- G040279-00-R Telecon on June, 15. 2004 8  Control »Using internal modulation with 33MHz Mach-Zehnder on 40m PSL

9. LIGO- G040279-00-R Telecon on June, 15. 2004 9 Other issue  Amplitude noise »Band width=100Hz »Not a problem.  Mode matching »Will be a loss at MC, not a problem.  Frequency noise »By Doppler shift or beam jitter, not a big issue.  Carrier phase fluctuation caused by shake of EOMs »Will be shown on demodulation phase, probably OK.

10. LIGO- G040279-00-R Telecon on June, 15. 2004 10 Mach-Zehnder on 40m PSL PZT mirror BS1 BS2 PMC 33MHz EOM 166MHz EOM 29MHz EOM To PD