= Simulation meeting 2022 Jun 2 15:00 =
Zoom2: https://zoom.us/j/6676627462

== Participants ==
Naoki Koyama, June Gyu Park, Yoichi Aso, Kentaro Somiya, Matteo Leonardi, Marc Eisenmann, Haoyu Wang

== Agenda ==

=== Updates from Projects ===

 * Birefringence simulation
   * We performed a very preliminary alignment sensing simulation for birefringence with single arm cavity [[ https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=14152|slide]].
   * Birefringence does not affect the operating point of the PDH error signal.
   * The birefringence in ITM will add distortion to the s-pol beam, introducing TEM01 (or TEM10) mode. This will generate an offset to the wavefront sensing error signal even though the cavity is well aligned.
   * This offset seems constant if the beam position on the ITM doesn't change. It probably can be compensated by looking at the transmission power of the cavity.
   * But when the beam position on the ITM changes, this offset will change. We need more accurate birefringence characterizations for KAGRA ITMs.