[Yuhang, Yao-Chin]
When dithering loop was open, we recorded that IR transmission modes correspond to AOM frequency (entry 1701) without parametric amplification of BAB which power was 318 uW. The result was as follows, mode matching was around 89.9%. We could realign suspension of BS and INPUT mirrors to reduce high-order modes. After aligning mirrors and dithering loop was closed, IR transmission was 405. At same time, we observed the GR and IR transmission signals during ten minutes as shown Fig 2. After ten minutes, IR and GR were misaligned obviously with decreased 16% and 4%, respectively. The CCD camera image changed from Fig 3 to Fig 4. Today, the filter cavity was unstable.
| Mode | IR transmission (average value) | AOM frequency (MHz) | Difference -109.03565 (MHz) |
| HG00(TEM00) | 370 | 109.03565 | 0 |
| HG10 (Yaw) | 115 | 109.43133 | 0.39568 |
| HG01 (Pitch) | 100 | 109.43223 | 0.39658 |
| HG11 | 98 | 109.82843 | 0.79278 |
| HG02 | 96 | 109.82922 | 0.79357 |
| HG20 | 97 | 109.83783 | 0.80218 |
| Background | 95 |
Note: From CCD camera image showed to define mode as Fig 1.
