  To make precision measurements with a CsI(Tl) calorimeter in a high
luminosity environment requires that the crystals are well calibrated and
continually monitored for radiation damage. This should not effect the total
integrated luminosity which is particularly important for the \babar
calorimeter to enable it to make CP violation measurements in the $B$ meson
system. To achieve this goal a fibre-optic light pulser system was designed
using xenon flash lamps as the light source. A novel light distribution method
was developed using an array of graded index microlenses. Some initial results
from performance studies are presented.
