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| OMG Kevin put some stuff here. | = Balanced Homodyne Detection = ==== Requirements ==== 1. Displacement noise of OMC/LMC mirrors 1. Scatter loss in mirrors 1. Cavity design: triangle, quad ring, quad zig-zag (reference the new OMC paper from Koji) 1. Laser amplitude / frequency noise including DC offsets in various other lock points and motions to simulate bilinear noise 1. Oscillator noise: AM / FM 1. Aux length noise: MICH/PRC/ SRC 1. Req. on offsets/asymmetries: arm finesse, arm reflectivity, mass imbalance of ETMs 1. Phase noise of LO 1. Polarization stability requirement for polarization BHD 1. Backscatter ==== Action items ==== * Design SRC so that 1. Suppress 02/20 modes 1. Partially transmit 01/10 modes for AS WFS 1. Suppress thermally generated modes 1. After the above have been satisfied, choose transmission to maximize ponderomotive squeezing * Budget above noises, but especially investigate polarization stability. * How is homodyne angle controlled? * Beam routing * Where to pick off LO? * Can we use ETMX transmission for LO? (Koji is crazy) * A+ BHD noise budget for both baseline double OMC and polarization BHD. ==== Modeling/Noise Budget ==== * Some BHD modeling is done in the OptimalGWextraction repo [[https://github.com/CaltechExperimentalGravity/OptimalGWextraction/tree/master/PonderSqueeze/BHD|here]]. ==== Polarization BHD ==== * [[https://dcc.ligo.org/LIGO-G1802013|Some thoughts on polarization BHD (LIGO-G1802013)]] * [[attachment:OMC.pdf|Polarization BHD notes]] ==== Other Links ==== * [[https://wiki.ligo.org/AIC/BHD_A_plus|A+ BHD wiki]] * [[https://wiki.ligo.org/AIC/BHD_MIT_WS|MIT A+ BHD workshop wiki]] |
Balanced Homodyne Detection
Requirements
- Displacement noise of OMC/LMC mirrors
- Scatter loss in mirrors
- Cavity design: triangle, quad ring, quad zig-zag (reference the new OMC paper from Koji)
- Laser amplitude / frequency noise including DC offsets in various other lock points and motions to simulate bilinear noise
- Oscillator noise: AM / FM
- Aux length noise: MICH/PRC/ SRC
- Req. on offsets/asymmetries: arm finesse, arm reflectivity, mass imbalance of ETMs
- Phase noise of LO
- Polarization stability requirement for polarization BHD
- Backscatter
Action items
- Design SRC so that
- Suppress 02/20 modes
- Partially transmit 01/10 modes for AS WFS
- Suppress thermally generated modes
- After the above have been satisfied, choose transmission to maximize ponderomotive squeezing
- Budget above noises, but especially investigate polarization stability.
- How is homodyne angle controlled?
- Beam routing
- Where to pick off LO?
- Can we use ETMX transmission for LO? (Koji is crazy)
- A+ BHD noise budget for both baseline double OMC and polarization BHD.
Modeling/Noise Budget
Some BHD modeling is done in the OptimalGWextraction repo here.
Polarization BHD
