  A UV laser calibration system is developed for the Jiangmen Underground
Neutrino Observatory (JUNO), a 20-kton liquid scintillator-based, long baseline
reactor anti-neutrino experiment. This system is capable of delivering fast
laser pulses (<1 ns) into the detector with a photon intensity ranging from
hundreds of keV to a few TeV equivalent energy. An independent intensity
monitoring system is developed for this laser, which has achieved a < 0.3%
relative uncertainty. Such a system will be used to calibrate the response of
the JUNO photosensors and electronics in situ to a sub-percent precision.
