Difference-frequency generation and parametric fluorescence in quasi-phase-matched lithium niobate stripe waveguides

Optical parametric oscillators (OPO) are excellent candidates for coherent tunable sources for many applications, such as telecommunications, spectroscopy and medicine, and optical parametric amplifiers (OPA) are interesting as amplifiers without spontaneous emission noise for generating squeezed states, etc… Integrated optical waveguide version1 of such devices could provide important additional features such as electrooptic tuning. Optical parametric fluorescence (OPF) and difference-frequency generation (DFG) are powerful techniques for characterizing the nonlinear waveguides without building the high-finesse cavity necessary to achieve the oscillation.