The video of laserdisc was/is analog, and originally the sound was as well. However not long after it started, they introduced digital sound on the laserdiscs. Those discs would be able to use the optical output of the laserdisc players and get true digital sound.

I transfered a few lasers (music titles) audio to my computer via the optical out > optical in, and noticed a my OLD (pre-digital sound) lasers wouldn't transfer via the optical out. So I believe that is ONLY for digital sound laserdiscs.

But the video was always analog.