Was it you that linked to the waveguide approach to LIDAR some time in the past six months or so? The advantage of doing it that way is it's cheap as fuck and your slew rate is in the MHz range. The disadvantage of doing it that way is you're limited to super low power lasers which means you're going to be limited in range by pure physics.
Yep 1, 2. I guess there's multiple ways to engineer it? "Lasers bounce off stuff" is near my limit on my knowledge on these things.