Hi , SE/30’s floppy drive is MP-F75W-xxG.
It is auto-inject drive. But 6100’s floppy drive is MPF xxA or MF355F-xxMA. It is manual-inject drive. They are not same, so you can’t use.
I will paste the link of the detailed page.
Discussion of Apple Macintosh SuperDrive floppy compatibility and interchangeability.
siber-sonic.com