Mode-coupling Cerenkov sum-frequency-generation in a multimode planar waveguide

We present experimental and theoretical studies of the mode-coupling Cerenkov sum-frequency radiations in a multimode LiNbO(3) planar waveguide. The radiations result from the coupling of different guided modes of the fundamental wave, which have the same optical frequencies but different propagation constants. At the same time, scattering-involved Cerenkov sum-frequency-generation was also observed and discussed. Our theoretical predictions are in well accordance with the experimental results. (C) 2010 American Institute of Physics. [doi:10.1063/1.3505359]