A fused silica light guide of 12cm length, 07mm circular input and 010,5mm hexagonal output cross sections was placed in the primary focus. Due to the existing difference in the input/output diameter dimensions, this light guide was used to reduce input angles smaller then 37° into output angles minor then 23° which matched well with the numerical aperture of the optical fibers. The light guide has also the function to homogenise the output light power at its output end, resulting in equal input light power distribution for the optical fibers. The hexagonal form of the output end of the light guide permits also the best light coupling with the fiber bundle. At the output end of the light guide, a bundle of 37 optical fibers was coupled, each of them with 1.5mm diameter. Mounting individually each of the 37 optical fibers into an aluminium part, a compact hexagonal bundle is formed.

SHAPE * MERGEFORMAT

0, 8

— 0,3 0,2