= Photodetectors =
== In-vac design considerations ==
 . [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10661 | Information from LIGO and VIRGO about in-vac PDs]]
 . [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10545 | PD feedthrough for ISS ]]


== Types ==
||Name ||Schematics ||Description ||
||RF PD ([[KAGRA/Subgroups/MIF/AEL/Photodetectors/RFPDList|List]]) ||[[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=1280|JGW-D1201280]] ||For IR. Same schematic for both in-air and in-vac, but in different kind of box. ||
||DC PD ||[[http://www.thorlabs.co.jp/thorproduct.cfm?partnumber=PDA100A|Thorlabs PDA100A]] ||For IR, in-air. ||
||RF QPD ([[KAGRA/Subgroups/MIF/AEL/Photodetectors/RFQPDList|List]]) ||[[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=2631|JGW-D1402631]] ||For IR. Same schematic for both in-air and in-vac, but in different kind of box. ||
||DC QPD ([[KAGRA/Subgroups/AOS/DCQPDList|List]], [[KAGRA/Subgroups/AOS/DCQPDDriverList|Driver List]]) ||[[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2411|JGW-D1402411]] ||For IR, in-air (same as oplev QPD for now). ||
||RF PD for green ||([[https://dcc.ligo.org/LIGO-D1002969/public|LIGO-D1002969]]) ||For green, in-air (could be BB). ||
||DC PD for green ||[[http://www.thorlabs.co.jp/thorproduct.cfm?partnumber=PDA100A|Thorlabs PDA100A]] ||For green, in-air (same for IR for now). ||
||DC QPD for green ||[[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2411|JGW-D1402411]] ||For green, in-air (same for IR for now). ||
||DC PD in vacuum ||([[https://dcc.ligo.org/LIGO-D1101059|LIGO-D1101059]]) ||For IR, in-vac. ||
||DC QPD in vacuum ||([[https://dcc.ligo.org/LIGO-T0900423/public|LIGO-T0900423]]) ||For IR, in-vac, bare QPD without amplifier. ||
||DC QPD in vacuum for green ||([[https://dcc.ligo.org/LIGO-T0900423/public|LIGO-T0900423]]) ||For green, in-vac, bare QPD without amplifier. ||


== List ==
See [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=2986|JGW-D1402986]] for location of photodetectors. See [[https://docs.google.com/spreadsheets/d/1EcuZOQP8yrD3s7no9PPGSxSD0V3NGAFvx799IeWH-1U/|this Google spreadsheet]] for list of photodetectors.

 * Modulation frequencies are listed in [[MIFIOOInterfaces]].

 * iKAGRA configuration (PMC: fPMC sideband / FRC: fIMC sideband / IMC: fIMC sideband, with ASC / 3-km MI: f1 sideband, without ASC / no ISS)

 * bKAGRA configuration (PMC: fPMC sideband / FRC: fIMC sideband / IMC: fIMC sideband, with ASC / DRFPMI: f1,f2,f3 sidebands, with ASC / ALS: fALSX,fALSY sidebands, without ASC / with ISS)

For aLIGO, PD/QPDs below are in vacuum (see [[https://dcc.ligo.org/LIGO-T1000264/public|LIGO-T1000264]]).

 * RF PDs for REFL, POP, AS

 * RF QPDs for REFL, AS

 * DC QPDs for MC2TRANS, POP, TRX, TRY, OMC (they don't have in air versions)