You can with fiber and it is allowed. I used these special plates[1] in my setup[2] that are meant to be run in the same conduit as power. Switzerland is quite strict with electrical codes so I was surprised when I found out I could do this.

[1] https://www.youtube.com/watch?v=ARSpp4B9-X4

[2] https://sschueller.github.io/posts/wiring-a-home-with-fiber/