[Takano, Ushiba]

To understand the current intensity noise of OMC transmission, we reduced OMC transmission power and compared the spectrum.
Figure 1 shows the spectrum when OMC transmission was 12.5 mW (red) and 26.3 mW (blue).
Even though OMC transmission power was reduced, intensity noise became worse.

Since the intensity noise was not scaled by the laser power, it is not likely the classical intensity noise injected to OMC.
It might be the coupling from controls such as OMC length, OMC ASC, CARM, and so on.
So, it is better to make noise budget to understand the current intensity noise.