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Mach-Zender interferometer to eliminate sidebands of sidebands for Advanced LIGO

Mach-Zender interferometer to eliminate sidebands of sidebands for Advanced LIGO Osamu Miyakawa, Caltech LIGO- G040279-00-R. Carrier. (Resonant on arms ). -f 2. -f 1. f 1. f 2. Signal extraction of AdvLIGO.

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Mach-Zender interferometer to eliminate sidebands of sidebands for Advanced LIGO

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

  2. Carrier (Resonant on arms) -f2 -f1 f1 f2 Signal extraction of AdvLIGO • Two sidebands are used to separate arm cavity signals andCentral part (Michelson, PR, SR) signals. • Arm cavity signals are extracted from beat between carrier and f1 or f2. • Central part (Michelson, PR, SR) signals are extracted from beat between f1 and f2, not including arm cavity information. • Single demodulation • Arms information • L+ and L- • Double/differential demodulation • Central part information • l+ , l- and ls Telecon on June, 15. 2004

  3. Sidebands of sidebands Simulation Real world • Sidebands of sidebands are produced by two series EOMs. • Beats between carrier and f2 +/- f1 disturb central part. • Sidebands of sidebands are amplitude modulation. Carrier Carrier -f2 -f1 f1 f2 -f2 -f1 f1 f2 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 Telecon on June, 15. 2004

  5. Signal matrix • Original signal matrix • Signal matrix with sideband of sideband 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? Telecon on June, 15. 2004

  7. To eliminate sidebands of sidebands PD • 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 EOM EOM PD EOM EOM FI Telecon on June, 15. 2004

  8. Mach-Zehnder on 40m PSL • Control • Using internal modulation with 33MHz 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. Telecon on June, 15. 2004

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

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