[_Mark_]

English is not my primary language - perhaps my searched didn't find anything relevant because I might have used the wrong words.

Usually, CO2 laser machines use the 3 mirrors and the focus lens to bring the light from the source (tube) to the target. This approach has several disadvantages in my opinion:

1. it requires a very precise setup of the mirrors
2. the machine should be developed keeping in mind the lights as to travel all around
3. any change in the mirrors alignment may lead to serious consequences
4. a complete enclosure of the machine is recommended to work as safe as possible

I wonder why is not possible to use a fiber optic to guide the laser to the focus lens.
Of course if nobody does it there's a reason! I'm just curious to know what is it.

By the way, all my searches led to "fiber laser" pages but that's another thing.

[cinematic2]

Because it is extremely expensive to colimate CO2 laser beam into fiber. CO2 is not 1064 nm but 10600 nm.
That needs special fiber, not glass fiber.