[Aritomi, Yuhang]

This is work on July 19th. In current setup, we only have one steering mirror and one lens for alignment of BAB going to homodyne and it's difficult to align BAB into AMC. So we changed optical layout so that we can have three steering mirrors for alignment of BAB. I updated optical layout of our bench. After this modification, we could align BAB to AMC easily. Re-alignment of IR to FC after this modification is ongoing.