  A Central Laser Facility is a system often used in astroparticle experiments
based on arrays of fluorescence or Cherenkov light detectors. The instrument is
based on a laser source positioned at a certain distance from the array,
emitting fast light pulses in the vertical direction with the aim of
calibrating the array and/or measuring the atmospheric transmission. In view of
the future Cherenkov Telescope Array (CTA), a similar device could provide a
calibration of the whole installation, both relative, i.e. each individual
telescope with respect to the rest of the array, and absolute, with a precision
better than 10%, if certain design requirements are met. Additionally, a
precise monitoring of the sensitivity of each telescope can be made on
time-scales of days to years. During calibration runs of the central laser
facility, all detectors will be pointed towards the same portion of the laser
beam at a given altitude. Simulations of the possible configurations of a
Central Laser Facility for CTA (varying laser energy, pointing height and
distance from the telescopes) have been performed
