[Chiaki Hirose, Haoyu Wang, Yuta Michimura]
 

  - Compared with the measurement in Nov 2023 (klog #27767), K1:LSC-TR_IRX_NORM_OUT_DQ seems noisy, and this is preventing us from seeing sideband beaks in the transmission. Not sure why it is noisier now (Different PD gains and/or whitening gains? Notch filters?).
 

We checked the past data and confirmed that the IMC output power was 9.8 W when Hirose-san did the cavity scan in Nov 2023 (Attachment #1), and it is now 1.2 W (Attachment #2). We also checked that the normalization factors in K1:TMS-X_IR_PDA1 and K1:LSC-TR_IRY_NORM filter banks were the same, and K1:LSC-TR_IRX_NORM_OUT_DQ is roughly one when Xarm was locked with PRM mis-aligned, suggesting that PD gains and whitening filter gains were the same (0dB for PD setting and no whitening gain). These explain why the noise level was about 10 times lower in Nov 2023.