To see the effect of coherent control beam on homodyne noise, I performed the measurement of the noise spectrum with LO or LO+CC on homodyne.

The result is attached as a figure from 10Hz to 51.2kHz. Coherent control beam brings a large 280Hz peak and several small peaks. Also, it rises up the noise level between 10Hz and 40Hz.

There are also videos show spectrum without average. Please refer to LO https://drive.google.com/open?id=12jaWRG_3HjDOSp6thXOixYxd7Y17WkIx, CC+LOhttps://drive.google.com/open?id=1OjRokr1ly4zR8Tf0TltP-oGDvwoo92RT

Notice that the signal of homodyne SUB-DC low-frequency noise spectrum has fluctuation. It means there are noise sometimes large and sometimes small. If we could float bench, it will be better.