= Optical Characterization =
This page is intended for summarizing the interferometer optical characterization results and discussions.
See following pages and documents for iKAGRA and bKAGRA Phase-1 characterization summary:
 * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5101|JGW-T160510 Summary of iKAGRA Test Run March 2016]]
 * [[KAGRA/Observation/iKAGRA/ChannelList|iKAGRA Channel List]]
 * [[KAGRA/Commissioning/Phase1/Operation/MeasurementsSummary|Phase 1 Measurements Summary]]
See following pages for some design parameters
 * [[KAGRA/Subgroups/IOO/OptParam|IOO related]]
 * [[KAGRA/Subgroups/IOO/OptParam|MIF related]]
Check also [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?dochttps://mail.google.com/mail/u/2/id=4014|MIR Document and Drawings Tree]]

== RF Sidebands ==
 * f1 frequency: 16.8732705 MHz https://klog.icrr.u-tokyo.ac.jp/osl/?r=4831
 * f2 frequency: 44.995388 MHz https://klog.icrr.u-tokyo.ac.jp/osl/?r=4831
 * f1 modulation depth: 0.22(2) using Y arm https://klog.icrr.u-tokyo.ac.jp/osl/?r=9505
  * 0.24(1) using X arm, before Harmonic Generator installation on 2019/2/14 https://klog.icrr.u-tokyo.ac.jp/osl/?r=7307
 * f2 modulation depth: 0.23(2) using Y arm https://klog.icrr.u-tokyo.ac.jp/osl/?r=9505
  * 0.0053(2) using X arm, before Harmonic Generator installation on 2019/2/14 https://klog.icrr.u-tokyo.ac.jp/osl/?r=7307

== Input Mode Cleaner ==
 * Round-trip length
  * '''Design''':   53.28708 m (FSR of 5.6269873 MHz)
  * '''Measured''': 53.302985(9) m B)
  * '''Measurement method''': FSR was measured to be 5.624308(1) MHz. https://klog.icrr.u-tokyo.ac.jp/osl/?r=4831
  * '''Notes''': Measured on April 2018. Any re-installation after this? Needs to be adjusted to match with PRC length.
 * Finesse
  * '''Design''': 520
  * '''Measured''': 409
  * '''Measurement method''': Cavity pole was measured to be 6.86(2) kHz. https://klog.icrr.u-tokyo.ac.jp/osl/?r=14569
  * '''Notes''': Lower than iKAGRA measurement of 540+/-70 http://klog.icrr.u-tokyo.ac.jp/osl/?r=618 Degraded? :o
 * Mode-match
  * '''Measured''':
  * '''Measurement method''':
  * '''Notes''':

== Arm Cavities ==
 * X-arm length
  * '''Design''': 3000 m
  * '''Measured''': 2999.990(2) m B)
  * '''Measurement method''': Cavity scan FSR = 49.96557(4) kHz http://klog.icrr.u-tokyo.ac.jp/osl/?r=7332
  * '''Notes''':
 * X-arm Gouy phase
  * '''Design''': 250.75 deg
  * '''Measured''': 250.7(3) deg
  * '''Measurement method''': Cavity scan TMS=34.79(5) kHz http://klog.icrr.u-tokyo.ac.jp/osl/?r=7332
  * '''Notes''':
 * X-arm finesse for IR
  * '''Design''': 1530
  * '''Measured''': 1410(30)
  * '''Measurement method''': Ring down
  * '''Notes''': There is temperature dependence due to frosting :o https://klog.icrr.u-tokyo.ac.jp/osl/?r=10033
 * X-arm round-trip loss
  * '''Design''': 100 ppm
  * '''Measured''': 86(3) ppm
  * '''Measurement method''': From reflectivity change in locked and unlocked https://klog.icrr.u-tokyo.ac.jp/osl/?r=7307
  * '''Notes''': The estimate might be wrong due to birefringence https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11633 :o
 * X-arm mode-match
  * '''Measured''': 91(1)%
  * '''Measurement method''': Cavity scan https://klog.icrr.u-tokyo.ac.jp/osl/?r=7307
  * '''Notes''':
 * X-arm finesse for green
  * '''Design''': 51
  * '''Measured''': 41(2)
  * '''Measurement method''': Calculated from reflectivity measurements by Hirose-san
  * '''Notes''':
 * Y-arm length
  * '''Design''': 3000 m
  * '''Measured''': 3000.015(1) m B)
  * '''Measurement method''': Cavity scan, FSR = 49.96517(2) kHz https://klog.icrr.u-tokyo.ac.jp/osl/?r=9505
  * '''Notes''':
 * Y-arm Gouy phase
  * '''Design''': 250.75 deg 
  * '''Measured''': 250.9(3) deg
  * '''Measurement method''': Cavity scan, TMS = 34.82(5) kHz https://klog.icrr.u-tokyo.ac.jp/osl/?r=9505
  * '''Notes''':
 * Y-arm finesse for IR
  * '''Design''': 1530
  * '''Measured''': 1320(30)
  * '''Measurement method''': Ring down, http://klog.icrr.u-tokyo.ac.jp/osl/?r=9052, http://klog.icrr.u-tokyo.ac.jp/osl/?r=9211, http://klog.icrr.u-tokyo.ac.jp/osl/?r=9496
  * '''Notes''': There is temperature dependence due to frosting :o https://klog.icrr.u-tokyo.ac.jp/osl/?r=10033
 * Y-arm round-trip loss
  * '''Design''': 100 ppm
  * '''Measured''': NOT YET MEASURED? :o
  * '''Measurement method''': https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11633
  * '''Notes''':
 * Y-arm mode-match
  * '''Measured''': 87(2) %
  * '''Measurement method''': Cavity scan https://klog.icrr.u-tokyo.ac.jp/osl/?r=9505
  * '''Notes''':
 * Y-arm finesse for green
  * '''Design''': 51
  * '''Measured''': 53(3)
  * '''Measurement method''': Calculated from reflectivity measurements by Hirose-san
  * '''Notes''':

== Power Recycling Cavity ==
 * PRX length
  * '''Design''': 68.2563 m (PRC length = 66.591 m)
  * '''Measured''': 68 m
  * '''Measurement method''': Using dnu/nu=dL/L https://klog.icrr.u-tokyo.ac.jp/osl/?r=14633
  * '''Notes''': Compare it with PRY.
 * PRY length
  * '''Design''': 64.9265 m
  * '''Measured''': 70.2 m
  * '''Measurement method''': Using dnu/nu=dL/L https://klog.icrr.u-tokyo.ac.jp/osl/?r=14565
  * '''Notes''': In consistent results between different methods and not compatible with Schnupp asymmetry measurement :o
 * PRC Gouy phase
  * '''Design''': 33.0 deg
  * '''Measured''': 31(1) deg
  * '''Measurement method''': Cavity scan with the inertia locking method http://klog.icrr.u-tokyo.ac.jp/osl/?r=9276
  * '''Notes''': After PR2 was moved. New measurement says 26.6 +/- 1.5 deg (round-trip) https://klog.icrr.u-tokyo.ac.jp/osl/?r=15179

== Signal Recycling Cavity ==
 * SRX length
  * '''Design''': 68.2563 m (SRC length = 66.591 m)
  * '''Measured''':
  * '''Measurement method''':
  * '''Notes''':
 * SRY length
  * '''Design''': 64.9265 m
  * '''Measured''':
  * '''Measurement method''':
  * '''Notes''':
 * SRC Gouy phase
  * '''Design''': 35.0
  * '''Measured''': 48(2) :o
  * '''Measurement method''': Cavity scan with the inertia locking method http://klog.icrr.u-tokyo.ac.jp/osl/?r=9246
  * '''Notes''': New measurement says 80.18 +/- 5.9 deg (round-trip) https://klog.icrr.u-tokyo.ac.jp/osl/?r=15179

== Michelson ==
 * Schnupp asymmetry
  * '''Design''': 3.3299 m
  * '''Measured''': 3.36(1) m
  * '''Measurement method''': Demodulation phase difference in locking X-arm and Y-arm  https://klog.icrr.u-tokyo.ac.jp/osl/?r=14575
  * '''Notes''': Not consistent with PRX and PRY measurements.

== Dual Recycled Michelson ==
 * Power recycling gain
  * '''Design''':
  * '''Measured''': ~3 :o
  * '''Measurement method''': REFERENCE TO BE ADDED
  * '''Notes''':
 * Power at each ISC detection ports when DRMI is locked
  * IMC output:
  * REFL:
  * POP p-pol:
  * POP s-pol:
  * POS p-pol:
  * POS s-pol:
  * AS RF:
  * OMC REFL:
  * OMC TRANS:
  * TRX:
  * TRY:

== Power Recycled Fabry-Perot Michelson ==
 * Power recycling gain for carrier
  * '''Design''': 10
  * '''Measured''': 10-12
  * '''Measurement method''': arm cavity transmitted power enhancement https://klog.icrr.u-tokyo.ac.jp/osl/?r=12639
  * '''Notes''': https://klog.icrr.u-tokyo.ac.jp/osl/?r=12643
 * Power recycling gain for f1 sideband
  * '''Design''':
  * '''Measured''':
  * '''Measurement method''':
  * '''Notes''':
 * Power recycling gain for f2 sideband
  * '''Design''':
  * '''Measured''':
  * '''Measurement method''':
  * '''Notes''':
 * Power at each ISC detection ports when PRFPMI is locked
  * IMC output:
  * REFL:
  * POP p-pol:
  * POP s-pol:
  * POS p-pol:
  * POS s-pol:
  * AS RF:
  * OMC REFL:
  * OMC TRANS:
  * TRX:
  * TRY:

== Output Mode Cleaner ==
 * Round-trip length
  * '''Design''': 1.5 m
  * '''Measured''': 2 * 0.717(2) m = 1.434(4) m
  * '''Measurement method''': Cavity scan FSR of 208.99(65) MHz https://klog.icrr.u-tokyo.ac.jp//?r=14696
  * '''Notes''':
 * Finesse
  * '''Design''': 780
  * '''Measured''': 616(62)
  * '''Measurement method''': Cavity scan https://klog.icrr.u-tokyo.ac.jp//?r=14696
  * '''Notes''':
 * AS mode content

== Sensing Matrix Measurements ==
 * LSC

 * ASC

== Optical Tables ==
I think we need a power budget here.

http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/IOO/OutputTables/Optics

IMC REFL (and TRANS): note that BSW11 is used (Ts=~40%, not 50%) https://klog.icrr.u-tokyo.ac.jp/osl/?r=3726

REFL table layout: note that p-pol is coming out from the chamber https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9238

POP table layout (Only cameras for POP s-pol and p-pol?) https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9623

POS table layout (DC PDs for POS s-pol and p-pol) https://klog.icrr.u-tokyo.ac.jp/osl/?r=14622

== Others ==
 * Laser intensity/frequency noise coupling
 * MICH/PRCL/SRCL to DARM coupling
 * MICH contrast defect
 * Type-A, B, Bp actuation efficiency measurements