I installed a FI for TEM00 PDH locking, and confirmed that one can pick off reflected beam with simple setup (QWP and mirror).
The attached picture shows the reflected beam picked up by FI.

Then, I continued the installation of optics.
However, I found that the height of FI was not good, which is not the one I mentioned but already installed one before.
So I modified the alignment.
Actually, the beam height is still higher than the target height, though I cannot adjust anymore.

So I am planning to install STMs in front of the EOM, which can adjust the beam height.