  Proposed as part of the next generation of water Cherenkov detectors,
Hyper-Kamiokande will have a vastly improved potential in determining leptonic
CP violation in neutrino oscillations. Well understood optical diffusers are
needed as part of an integrated light injection system for calibration of
ultrasenstive photo-detectors. Research and development into optical diffuser
technology is presented and summaries of recent installations in
Super-Kamiokande are discussed.
