You must be one LIGHT (pun intended) sleeper Good luck with your cat, attention seeking, nocturnal animal that most are!
I'm pretty sure that there are some opaque and semi-opaque doors out there. Be advised though that some cats won't/don't like to go thru something they can't see through at least a little. You could buff up a transparent door with sandpaper or use some non-toxic paint.
Maybe you could think of it as a night-light?

 

I have the same problem. I once could not sleep at a hotel because the hall lights were shining under the door. Then I rolled up the towels and laid them along the door and slept like a baby.
Anyway I have a cat door to the outside in my bedroom and the neighbors security lights shine through so I used a curtain in front of the cat door. The cats know that the door is there and they are always looking behind the curtains to see out the window anyway.

 

Thanks, Lyle. Light sleeper, ha ha... :crazy

And thanks, builder. I haven't thought of a curtain. Maybe I can try. rcatrcat

 

Did you ever find one ?