Aromaru, I seem to be as 'Crazy as a frog of foxes". However, except when I'm violating Clarke's first law, I'm usually pretty good at what I do. You may wish to quietly inquire from other PLers what I did for a living before the economy went south. I used to be very, very, good at what I did.
A look at a 6200 Kelvin spectrum for a black body compared to the adsorption curve of fused silica fiber might be in order. He can't afford a broad spectrum chalcogenide fiber. I can get him some huge medical fibers, but he can't make the required spot size to match the NA.
Relax,
Swami knows enough about optics to mock up what he's trying to do before he knocks a hole in his roof. Besides, he'll call my best friend, and they will go out in the desert and drink after they try this.
Chris,
If you can find a old Super-Trouper based on carbon arc (Possibly converted to xenon at one time), you might be amazed at the pyrex long focal lenses in the long throw versions, These can be had for the asking in many major cities as they are replaced with Xenon, Halide, and LED. You just want the lenses in their mounting rings, ditch the arc and body. I pulled a set out of two scrapped Troupers on campus a few years ago. They make nice burners.
Electronic Goldmine had some huge plastic 4 foot square Fresnels with 13 foot focal lengths about 3 years ago, They were not hot sellers. They might still have some. We bought one at the lab for a project, and got "burned" because Goldmine was "optomystic" (pun intended) on the focal length.
One meter square front surface mirrors show up in dead projection TVs by the road, all the time.
Remember to use a assist gas and fume evacuator, pine tar fumes are nasty.
Have fun,
Steve