The optical parametric fluorescence was observed for the first time in a guided wave structure. In contrast to bulk optics three processes occur: signal and idler photons belong both to guided modes or both to radia-ting substrate modes or one to a guided mode and the other to substrate modes. These processes were investigated experimentally in Ti:LiNb03-channel waveguides. Using a cw-argon laser (λ = 514 nm) or a pulsed dye laser (580 nm < λ < 615 nm) as pump source, the fluorescence was studied as function of the pump wavelength, the pump power, the waveguide temperature and of spatial filtering.
"Optical Parametric Fluorescence In Ti:LiNbO3 Channel Waveguides", Proc. SPIE 0651, Integrated Optical Circuit Engineering III, (3 November 1986); doi: 10.1117/12.938155; https://doi.org/10.1117/12.938155