Hey, we are trying to couple the light of a 75 W Xe Arc Lamp (Hamamatsu L2194) into a 800um(0,8mm) diameter fiber bundle (7 fibers). Now we have 2 plano convex lenses (25mm diameter, 30mm EFL, edmund serial #45-364), the first for collimating the second for focusing onto the fiber. We are trying to move the fiber bundle around the focus, so all the fibers in the bundle receive light, because the fibers close to the edge receive just a small portion of the light I would like to improve this. I looked up the arc lamp datasheet and found the radiant flux distribution. http://goo.gl/UR3C13 page 5 It seems they are radiating in a 100° cone, so I could replace the 25 mm lenses with bigger ones, so it could collect more light. Also i thought of replacing the lens material from N-BK7 to fused silica maybe, but from the xe lamp spectrum it may not be a good idea. I also thought of using a diffuser, but I do not have any experience with them. Maybe replacing the lamp with a bigger one? And finally I thought, maybe I could first focus the light into a 800um diameter fiber first, and then couple the light from it into the fiber bundle. I think the fiber would scrample the light distribution this way, am I correct in this?